Line data Source code
1 : /* Scalar evolution detector.
2 : Copyright (C) 2003-2026 Free Software Foundation, Inc.
3 : Contributed by Sebastian Pop <s.pop@laposte.net>
4 :
5 : This file is part of GCC.
6 :
7 : GCC is free software; you can redistribute it and/or modify it under
8 : the terms of the GNU General Public License as published by the Free
9 : Software Foundation; either version 3, or (at your option) any later
10 : version.
11 :
12 : GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 : WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 : FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 : for more details.
16 :
17 : You should have received a copy of the GNU General Public License
18 : along with GCC; see the file COPYING3. If not see
19 : <http://www.gnu.org/licenses/>. */
20 :
21 : /*
22 : Description:
23 :
24 : This pass analyzes the evolution of scalar variables in loop
25 : structures. The algorithm is based on the SSA representation,
26 : and on the loop hierarchy tree. This algorithm is not based on
27 : the notion of versions of a variable, as it was the case for the
28 : previous implementations of the scalar evolution algorithm, but
29 : it assumes that each defined name is unique.
30 :
31 : The notation used in this file is called "chains of recurrences",
32 : and has been proposed by Eugene Zima, Robert Van Engelen, and
33 : others for describing induction variables in programs. For example
34 : "b -> {0, +, 2}_1" means that the scalar variable "b" is equal to 0
35 : when entering in the loop_1 and has a step 2 in this loop, in other
36 : words "for (b = 0; b < N; b+=2);". Note that the coefficients of
37 : this chain of recurrence (or chrec [shrek]) can contain the name of
38 : other variables, in which case they are called parametric chrecs.
39 : For example, "b -> {a, +, 2}_1" means that the initial value of "b"
40 : is the value of "a". In most of the cases these parametric chrecs
41 : are fully instantiated before their use because symbolic names can
42 : hide some difficult cases such as self-references described later
43 : (see the Fibonacci example).
44 :
45 : A short sketch of the algorithm is:
46 :
47 : Given a scalar variable to be analyzed, follow the SSA edge to
48 : its definition:
49 :
50 : - When the definition is a GIMPLE_ASSIGN: if the right hand side
51 : (RHS) of the definition cannot be statically analyzed, the answer
52 : of the analyzer is: "don't know".
53 : Otherwise, for all the variables that are not yet analyzed in the
54 : RHS, try to determine their evolution, and finally try to
55 : evaluate the operation of the RHS that gives the evolution
56 : function of the analyzed variable.
57 :
58 : - When the definition is a condition-phi-node: determine the
59 : evolution function for all the branches of the phi node, and
60 : finally merge these evolutions (see chrec_merge).
61 :
62 : - When the definition is a loop-phi-node: determine its initial
63 : condition, that is the SSA edge defined in an outer loop, and
64 : keep it symbolic. Then determine the SSA edges that are defined
65 : in the body of the loop. Follow the inner edges until ending on
66 : another loop-phi-node of the same analyzed loop. If the reached
67 : loop-phi-node is not the starting loop-phi-node, then we keep
68 : this definition under a symbolic form. If the reached
69 : loop-phi-node is the same as the starting one, then we compute a
70 : symbolic stride on the return path. The result is then the
71 : symbolic chrec {initial_condition, +, symbolic_stride}_loop.
72 :
73 : Examples:
74 :
75 : Example 1: Illustration of the basic algorithm.
76 :
77 : | a = 3
78 : | loop_1
79 : | b = phi (a, c)
80 : | c = b + 1
81 : | if (c > 10) exit_loop
82 : | endloop
83 :
84 : Suppose that we want to know the number of iterations of the
85 : loop_1. The exit_loop is controlled by a COND_EXPR (c > 10). We
86 : ask the scalar evolution analyzer two questions: what's the
87 : scalar evolution (scev) of "c", and what's the scev of "10". For
88 : "10" the answer is "10" since it is a scalar constant. For the
89 : scalar variable "c", it follows the SSA edge to its definition,
90 : "c = b + 1", and then asks again what's the scev of "b".
91 : Following the SSA edge, we end on a loop-phi-node "b = phi (a,
92 : c)", where the initial condition is "a", and the inner loop edge
93 : is "c". The initial condition is kept under a symbolic form (it
94 : may be the case that the copy constant propagation has done its
95 : work and we end with the constant "3" as one of the edges of the
96 : loop-phi-node). The update edge is followed to the end of the
97 : loop, and until reaching again the starting loop-phi-node: b -> c
98 : -> b. At this point we have drawn a path from "b" to "b" from
99 : which we compute the stride in the loop: in this example it is
100 : "+1". The resulting scev for "b" is "b -> {a, +, 1}_1". Now
101 : that the scev for "b" is known, it is possible to compute the
102 : scev for "c", that is "c -> {a + 1, +, 1}_1". In order to
103 : determine the number of iterations in the loop_1, we have to
104 : instantiate_parameters (loop_1, {a + 1, +, 1}_1), that gives after some
105 : more analysis the scev {4, +, 1}_1, or in other words, this is
106 : the function "f (x) = x + 4", where x is the iteration count of
107 : the loop_1. Now we have to solve the inequality "x + 4 > 10",
108 : and take the smallest iteration number for which the loop is
109 : exited: x = 7. This loop runs from x = 0 to x = 7, and in total
110 : there are 8 iterations. In terms of loop normalization, we have
111 : created a variable that is implicitly defined, "x" or just "_1",
112 : and all the other analyzed scalars of the loop are defined in
113 : function of this variable:
114 :
115 : a -> 3
116 : b -> {3, +, 1}_1
117 : c -> {4, +, 1}_1
118 :
119 : or in terms of a C program:
120 :
121 : | a = 3
122 : | for (x = 0; x <= 7; x++)
123 : | {
124 : | b = x + 3
125 : | c = x + 4
126 : | }
127 :
128 : Example 2a: Illustration of the algorithm on nested loops.
129 :
130 : | loop_1
131 : | a = phi (1, b)
132 : | c = a + 2
133 : | loop_2 10 times
134 : | b = phi (c, d)
135 : | d = b + 3
136 : | endloop
137 : | endloop
138 :
139 : For analyzing the scalar evolution of "a", the algorithm follows
140 : the SSA edge into the loop's body: "a -> b". "b" is an inner
141 : loop-phi-node, and its analysis as in Example 1, gives:
142 :
143 : b -> {c, +, 3}_2
144 : d -> {c + 3, +, 3}_2
145 :
146 : Following the SSA edge for the initial condition, we end on "c = a
147 : + 2", and then on the starting loop-phi-node "a". From this point,
148 : the loop stride is computed: back on "c = a + 2" we get a "+2" in
149 : the loop_1, then on the loop-phi-node "b" we compute the overall
150 : effect of the inner loop that is "b = c + 30", and we get a "+30"
151 : in the loop_1. That means that the overall stride in loop_1 is
152 : equal to "+32", and the result is:
153 :
154 : a -> {1, +, 32}_1
155 : c -> {3, +, 32}_1
156 :
157 : Example 2b: Multivariate chains of recurrences.
158 :
159 : | loop_1
160 : | k = phi (0, k + 1)
161 : | loop_2 4 times
162 : | j = phi (0, j + 1)
163 : | loop_3 4 times
164 : | i = phi (0, i + 1)
165 : | A[j + k] = ...
166 : | endloop
167 : | endloop
168 : | endloop
169 :
170 : Analyzing the access function of array A with
171 : instantiate_parameters (loop_1, "j + k"), we obtain the
172 : instantiation and the analysis of the scalar variables "j" and "k"
173 : in loop_1. This leads to the scalar evolution {4, +, 1}_1: the end
174 : value of loop_2 for "j" is 4, and the evolution of "k" in loop_1 is
175 : {0, +, 1}_1. To obtain the evolution function in loop_3 and
176 : instantiate the scalar variables up to loop_1, one has to use:
177 : instantiate_scev (block_before_loop (loop_1), loop_3, "j + k").
178 : The result of this call is {{0, +, 1}_1, +, 1}_2.
179 :
180 : Example 3: Higher degree polynomials.
181 :
182 : | loop_1
183 : | a = phi (2, b)
184 : | c = phi (5, d)
185 : | b = a + 1
186 : | d = c + a
187 : | endloop
188 :
189 : a -> {2, +, 1}_1
190 : b -> {3, +, 1}_1
191 : c -> {5, +, a}_1
192 : d -> {5 + a, +, a}_1
193 :
194 : instantiate_parameters (loop_1, {5, +, a}_1) -> {5, +, 2, +, 1}_1
195 : instantiate_parameters (loop_1, {5 + a, +, a}_1) -> {7, +, 3, +, 1}_1
196 :
197 : Example 4: Lucas, Fibonacci, or mixers in general.
198 :
199 : | loop_1
200 : | a = phi (1, b)
201 : | c = phi (3, d)
202 : | b = c
203 : | d = c + a
204 : | endloop
205 :
206 : a -> (1, c)_1
207 : c -> {3, +, a}_1
208 :
209 : The syntax "(1, c)_1" stands for a PEELED_CHREC that has the
210 : following semantics: during the first iteration of the loop_1, the
211 : variable contains the value 1, and then it contains the value "c".
212 : Note that this syntax is close to the syntax of the loop-phi-node:
213 : "a -> (1, c)_1" vs. "a = phi (1, c)".
214 :
215 : The symbolic chrec representation contains all the semantics of the
216 : original code. What is more difficult is to use this information.
217 :
218 : Example 5: Flip-flops, or exchangers.
219 :
220 : | loop_1
221 : | a = phi (1, b)
222 : | c = phi (3, d)
223 : | b = c
224 : | d = a
225 : | endloop
226 :
227 : a -> (1, c)_1
228 : c -> (3, a)_1
229 :
230 : Based on these symbolic chrecs, it is possible to refine this
231 : information into the more precise PERIODIC_CHRECs:
232 :
233 : a -> |1, 3|_1
234 : c -> |3, 1|_1
235 :
236 : This transformation is not yet implemented.
237 :
238 : Further readings:
239 :
240 : You can find a more detailed description of the algorithm in:
241 : http://icps.u-strasbg.fr/~pop/DEA_03_Pop.pdf
242 : http://icps.u-strasbg.fr/~pop/DEA_03_Pop.ps.gz. But note that
243 : this is a preliminary report and some of the details of the
244 : algorithm have changed. I'm working on a research report that
245 : updates the description of the algorithms to reflect the design
246 : choices used in this implementation.
247 :
248 : A set of slides show a high level overview of the algorithm and run
249 : an example through the scalar evolution analyzer:
250 : http://cri.ensmp.fr/~pop/gcc/mar04/slides.pdf
251 :
252 : The slides that I have presented at the GCC Summit'04 are available
253 : at: http://cri.ensmp.fr/~pop/gcc/20040604/gccsummit-lno-spop.pdf
254 : */
255 :
256 : #include "config.h"
257 : #include "system.h"
258 : #include "coretypes.h"
259 : #include "backend.h"
260 : #include "target.h"
261 : #include "rtl.h"
262 : #include "optabs-query.h"
263 : #include "tree.h"
264 : #include "gimple.h"
265 : #include "ssa.h"
266 : #include "gimple-pretty-print.h"
267 : #include "fold-const.h"
268 : #include "gimplify.h"
269 : #include "gimple-iterator.h"
270 : #include "gimplify-me.h"
271 : #include "tree-cfg.h"
272 : #include "tree-ssa-loop-ivopts.h"
273 : #include "tree-ssa-loop-manip.h"
274 : #include "tree-ssa-loop-niter.h"
275 : #include "tree-ssa-loop.h"
276 : #include "tree-ssa.h"
277 : #include "cfgloop.h"
278 : #include "tree-chrec.h"
279 : #include "tree-affine.h"
280 : #include "tree-scalar-evolution.h"
281 : #include "dumpfile.h"
282 : #include "tree-ssa-propagate.h"
283 : #include "gimple-fold.h"
284 : #include "tree-into-ssa.h"
285 : #include "builtins.h"
286 : #include "case-cfn-macros.h"
287 : #include "tree-eh.h"
288 :
289 : static tree analyze_scalar_evolution_1 (class loop *, tree);
290 : static tree analyze_scalar_evolution_for_address_of (class loop *loop,
291 : tree var);
292 :
293 : /* The cached information about an SSA name with version NAME_VERSION,
294 : claiming that below basic block with index INSTANTIATED_BELOW, the
295 : value of the SSA name can be expressed as CHREC. */
296 :
297 : struct GTY((for_user)) scev_info_str {
298 : unsigned int name_version;
299 : int instantiated_below;
300 : tree chrec;
301 : };
302 :
303 : /* Counters for the scev database. */
304 : static unsigned nb_set_scev = 0;
305 : static unsigned nb_get_scev = 0;
306 :
307 : struct scev_info_hasher : ggc_ptr_hash<scev_info_str>
308 : {
309 : static hashval_t hash (scev_info_str *i);
310 : static bool equal (const scev_info_str *a, const scev_info_str *b);
311 : };
312 :
313 : static GTY (()) hash_table<scev_info_hasher> *scalar_evolution_info;
314 :
315 :
316 : /* Constructs a new SCEV_INFO_STR structure for VAR and INSTANTIATED_BELOW. */
317 :
318 : static inline struct scev_info_str *
319 52291564 : new_scev_info_str (basic_block instantiated_below, tree var)
320 : {
321 52291564 : struct scev_info_str *res;
322 :
323 52291564 : res = ggc_alloc<scev_info_str> ();
324 52291564 : res->name_version = SSA_NAME_VERSION (var);
325 52291564 : res->chrec = chrec_not_analyzed_yet;
326 52291564 : res->instantiated_below = instantiated_below->index;
327 :
328 52291564 : return res;
329 : }
330 :
331 : /* Computes a hash function for database element ELT. */
332 :
333 : hashval_t
334 1066773638 : scev_info_hasher::hash (scev_info_str *elt)
335 : {
336 1066773638 : return elt->name_version ^ elt->instantiated_below;
337 : }
338 :
339 : /* Compares database elements E1 and E2. */
340 :
341 : bool
342 1057343204 : scev_info_hasher::equal (const scev_info_str *elt1, const scev_info_str *elt2)
343 : {
344 1057343204 : return (elt1->name_version == elt2->name_version
345 1057343204 : && elt1->instantiated_below == elt2->instantiated_below);
346 : }
347 :
348 : /* Get the scalar evolution of VAR for INSTANTIATED_BELOW basic block.
349 : A first query on VAR returns chrec_not_analyzed_yet. */
350 :
351 : static tree *
352 205658040 : find_var_scev_info (basic_block instantiated_below, tree var)
353 : {
354 205658040 : struct scev_info_str *res;
355 205658040 : struct scev_info_str tmp;
356 :
357 205658040 : tmp.name_version = SSA_NAME_VERSION (var);
358 205658040 : tmp.instantiated_below = instantiated_below->index;
359 205658040 : scev_info_str **slot = scalar_evolution_info->find_slot (&tmp, INSERT);
360 :
361 205658040 : if (!*slot)
362 52291564 : *slot = new_scev_info_str (instantiated_below, var);
363 205658040 : res = *slot;
364 :
365 205658040 : return &res->chrec;
366 : }
367 :
368 :
369 : /* Hashtable helpers for a temporary hash-table used when
370 : analyzing a scalar evolution, instantiating a CHREC or
371 : resolving mixers. */
372 :
373 : class instantiate_cache_type
374 : {
375 : public:
376 : htab_t map;
377 : vec<scev_info_str> entries;
378 :
379 129699451 : instantiate_cache_type () : map (NULL), entries (vNULL) {}
380 : ~instantiate_cache_type ();
381 126749620 : tree get (unsigned slot) { return entries[slot].chrec; }
382 98227148 : void set (unsigned slot, tree chrec) { entries[slot].chrec = chrec; }
383 : };
384 :
385 129699451 : instantiate_cache_type::~instantiate_cache_type ()
386 : {
387 129699451 : if (map != NULL)
388 : {
389 29107200 : htab_delete (map);
390 29107200 : entries.release ();
391 : }
392 129699451 : }
393 :
394 : /* Cache to avoid infinite recursion when instantiating an SSA name.
395 : Live during the outermost analyze_scalar_evolution, instantiate_scev
396 : or resolve_mixers call. */
397 : static instantiate_cache_type *global_cache;
398 :
399 :
400 : /* Return true when PHI is a loop-phi-node. */
401 :
402 : static bool
403 25913188 : loop_phi_node_p (gimple *phi)
404 : {
405 : /* The implementation of this function is based on the following
406 : property: "all the loop-phi-nodes of a loop are contained in the
407 : loop's header basic block". */
408 :
409 0 : return loop_containing_stmt (phi)->header == gimple_bb (phi);
410 : }
411 :
412 : /* Compute the scalar evolution for EVOLUTION_FN after crossing LOOP.
413 : In general, in the case of multivariate evolutions we want to get
414 : the evolution in different loops. LOOP specifies the level for
415 : which to get the evolution.
416 :
417 : Example:
418 :
419 : | for (j = 0; j < 100; j++)
420 : | {
421 : | for (k = 0; k < 100; k++)
422 : | {
423 : | i = k + j; - Here the value of i is a function of j, k.
424 : | }
425 : | ... = i - Here the value of i is a function of j.
426 : | }
427 : | ... = i - Here the value of i is a scalar.
428 :
429 : Example:
430 :
431 : | i_0 = ...
432 : | loop_1 10 times
433 : | i_1 = phi (i_0, i_2)
434 : | i_2 = i_1 + 2
435 : | endloop
436 :
437 : This loop has the same effect as:
438 : LOOP_1 has the same effect as:
439 :
440 : | i_1 = i_0 + 20
441 :
442 : The overall effect of the loop, "i_0 + 20" in the previous example,
443 : is obtained by passing in the parameters: LOOP = 1,
444 : EVOLUTION_FN = {i_0, +, 2}_1.
445 : */
446 :
447 : tree
448 5733783 : compute_overall_effect_of_inner_loop (class loop *loop, tree evolution_fn)
449 : {
450 6627132 : bool val = false;
451 :
452 6627132 : if (evolution_fn == chrec_dont_know)
453 : return chrec_dont_know;
454 :
455 6508243 : else if (TREE_CODE (evolution_fn) == POLYNOMIAL_CHREC)
456 : {
457 2476250 : class loop *inner_loop = get_chrec_loop (evolution_fn);
458 :
459 2476250 : if (inner_loop == loop
460 2476250 : || flow_loop_nested_p (loop, inner_loop))
461 : {
462 2476250 : tree nb_iter = number_of_latch_executions (inner_loop);
463 :
464 2476250 : if (nb_iter == chrec_dont_know)
465 : return chrec_dont_know;
466 : else
467 : {
468 893349 : tree res;
469 :
470 : /* evolution_fn is the evolution function in LOOP. Get
471 : its value in the nb_iter-th iteration. */
472 893349 : res = chrec_apply (inner_loop->num, evolution_fn, nb_iter);
473 :
474 893349 : if (chrec_contains_symbols_defined_in_loop (res, loop->num))
475 61600 : res = instantiate_parameters (loop, res);
476 :
477 : /* Continue the computation until ending on a parent of LOOP. */
478 893349 : return compute_overall_effect_of_inner_loop (loop, res);
479 : }
480 : }
481 : else
482 : return evolution_fn;
483 : }
484 :
485 : /* If the evolution function is an invariant, there is nothing to do. */
486 4031993 : else if (no_evolution_in_loop_p (evolution_fn, loop->num, &val) && val)
487 : return evolution_fn;
488 :
489 : else
490 3251665 : return chrec_dont_know;
491 : }
492 :
493 : /* Associate CHREC to SCALAR. */
494 :
495 : static void
496 49766980 : set_scalar_evolution (basic_block instantiated_below, tree scalar, tree chrec)
497 : {
498 49766980 : tree *scalar_info;
499 :
500 49766980 : if (TREE_CODE (scalar) != SSA_NAME)
501 : return;
502 :
503 49766980 : scalar_info = find_var_scev_info (instantiated_below, scalar);
504 :
505 49766980 : if (dump_file)
506 : {
507 84444 : if (dump_flags & TDF_SCEV)
508 : {
509 11 : fprintf (dump_file, "(set_scalar_evolution \n");
510 11 : fprintf (dump_file, " instantiated_below = %d \n",
511 : instantiated_below->index);
512 11 : fprintf (dump_file, " (scalar = ");
513 11 : print_generic_expr (dump_file, scalar);
514 11 : fprintf (dump_file, ")\n (scalar_evolution = ");
515 11 : print_generic_expr (dump_file, chrec);
516 11 : fprintf (dump_file, "))\n");
517 : }
518 84444 : if (dump_flags & TDF_STATS)
519 7216 : nb_set_scev++;
520 : }
521 :
522 49766980 : *scalar_info = chrec;
523 : }
524 :
525 : /* Retrieve the chrec associated to SCALAR instantiated below
526 : INSTANTIATED_BELOW block. */
527 :
528 : static tree
529 193628608 : get_scalar_evolution (basic_block instantiated_below, tree scalar)
530 : {
531 193628608 : tree res;
532 :
533 193628608 : if (dump_file)
534 : {
535 691593 : if (dump_flags & TDF_SCEV)
536 : {
537 36 : fprintf (dump_file, "(get_scalar_evolution \n");
538 36 : fprintf (dump_file, " (scalar = ");
539 36 : print_generic_expr (dump_file, scalar);
540 36 : fprintf (dump_file, ")\n");
541 : }
542 691593 : if (dump_flags & TDF_STATS)
543 50926 : nb_get_scev++;
544 : }
545 :
546 193628608 : if (VECTOR_TYPE_P (TREE_TYPE (scalar))
547 193628608 : || TREE_CODE (TREE_TYPE (scalar)) == COMPLEX_TYPE)
548 : /* For chrec_dont_know we keep the symbolic form. */
549 : res = scalar;
550 : else
551 193326606 : switch (TREE_CODE (scalar))
552 : {
553 157977150 : case SSA_NAME:
554 157977150 : if (SSA_NAME_IS_DEFAULT_DEF (scalar))
555 : res = scalar;
556 : else
557 155891060 : res = *find_var_scev_info (instantiated_below, scalar);
558 : break;
559 :
560 : case REAL_CST:
561 : case FIXED_CST:
562 : case INTEGER_CST:
563 : res = scalar;
564 : break;
565 :
566 : default:
567 193628608 : res = chrec_not_analyzed_yet;
568 : break;
569 : }
570 :
571 193628608 : if (dump_file && (dump_flags & TDF_SCEV))
572 : {
573 36 : fprintf (dump_file, " (scalar_evolution = ");
574 36 : print_generic_expr (dump_file, res);
575 36 : fprintf (dump_file, "))\n");
576 : }
577 :
578 193628608 : return res;
579 : }
580 :
581 :
582 : /* Depth first search algorithm. */
583 :
584 : enum t_bool {
585 : t_false,
586 : t_true,
587 : t_dont_know
588 : };
589 :
590 : class scev_dfs
591 : {
592 : public:
593 10745272 : scev_dfs (class loop *loop_, gphi *phi_, tree init_cond_)
594 10745272 : : loop (loop_), loop_phi_node (phi_), init_cond (init_cond_) {}
595 : t_bool get_ev (tree *, tree);
596 :
597 : private:
598 : t_bool follow_ssa_edge_expr (gimple *, tree, tree *, int);
599 : t_bool follow_ssa_edge_binary (gimple *at_stmt,
600 : tree type, tree rhs0, enum tree_code code,
601 : tree rhs1, tree *evolution_of_loop, int limit);
602 : t_bool follow_ssa_edge_in_condition_phi_branch (int i,
603 : gphi *condition_phi,
604 : tree *evolution_of_branch,
605 : tree init_cond, int limit);
606 : t_bool follow_ssa_edge_in_condition_phi (gphi *condition_phi,
607 : tree *evolution_of_loop, int limit);
608 : t_bool follow_ssa_edge_inner_loop_phi (gphi *loop_phi_node,
609 : tree *evolution_of_loop, int limit);
610 : tree add_to_evolution (tree chrec_before, enum tree_code code,
611 : tree to_add, gimple *at_stmt);
612 : tree add_to_evolution_1 (tree chrec_before, tree to_add, gimple *at_stmt);
613 :
614 : class loop *loop;
615 : gphi *loop_phi_node;
616 : tree init_cond;
617 : };
618 :
619 : t_bool
620 10745272 : scev_dfs::get_ev (tree *ev_fn, tree arg)
621 : {
622 10745272 : *ev_fn = chrec_dont_know;
623 10745272 : return follow_ssa_edge_expr (loop_phi_node, arg, ev_fn, 0);
624 : }
625 :
626 : /* Helper function for add_to_evolution. Returns the evolution
627 : function for an assignment of the form "a = b + c", where "a" and
628 : "b" are on the strongly connected component. CHREC_BEFORE is the
629 : information that we already have collected up to this point.
630 : TO_ADD is the evolution of "c".
631 :
632 : When CHREC_BEFORE has an evolution part in LOOP_NB, add to this
633 : evolution the expression TO_ADD, otherwise construct an evolution
634 : part for this loop. */
635 :
636 : tree
637 8898091 : scev_dfs::add_to_evolution_1 (tree chrec_before, tree to_add, gimple *at_stmt)
638 : {
639 8898091 : tree type, left, right;
640 8898091 : unsigned loop_nb = loop->num;
641 8898091 : class loop *chloop;
642 :
643 8898091 : switch (TREE_CODE (chrec_before))
644 : {
645 156311 : case POLYNOMIAL_CHREC:
646 156311 : chloop = get_chrec_loop (chrec_before);
647 156311 : if (chloop == loop
648 156311 : || flow_loop_nested_p (chloop, loop))
649 : {
650 156311 : unsigned var;
651 :
652 156311 : type = chrec_type (chrec_before);
653 :
654 : /* When there is no evolution part in this loop, build it. */
655 156311 : if (chloop != loop)
656 : {
657 0 : var = loop_nb;
658 0 : left = chrec_before;
659 0 : right = SCALAR_FLOAT_TYPE_P (type)
660 0 : ? build_real (type, dconst0)
661 0 : : build_int_cst (type, 0);
662 : }
663 : else
664 : {
665 156311 : var = CHREC_VARIABLE (chrec_before);
666 156311 : left = CHREC_LEFT (chrec_before);
667 156311 : right = CHREC_RIGHT (chrec_before);
668 : }
669 :
670 156311 : to_add = chrec_convert (type, to_add, at_stmt);
671 156311 : right = chrec_convert_rhs (type, right, at_stmt);
672 156311 : right = chrec_fold_plus (chrec_type (right), right, to_add);
673 : /* When we have an evolution in a non-wrapping type and
674 : in the process of accumulating CHREC_RIGHT there was
675 : overflow this indicates in the association that happened
676 : in building the CHREC clearly involved UB. Avoid this.
677 : In building a CHREC we basically turn (a + INCR1) + INCR2
678 : into a + (INCR1 + INCR2) which is not always valid.
679 : Note this check only catches few invalid cases. */
680 77739 : if ((INTEGRAL_TYPE_P (type) && ! TYPE_OVERFLOW_WRAPS (type))
681 39289 : && TREE_CODE (right) == INTEGER_CST
682 165447 : && TREE_OVERFLOW (right))
683 5 : return chrec_dont_know;
684 156306 : return build_polynomial_chrec (var, left, right);
685 : }
686 : else
687 : {
688 0 : gcc_assert (flow_loop_nested_p (loop, chloop));
689 :
690 : /* Search the evolution in LOOP_NB. */
691 0 : left = add_to_evolution_1 (CHREC_LEFT (chrec_before),
692 : to_add, at_stmt);
693 0 : right = CHREC_RIGHT (chrec_before);
694 0 : right = chrec_convert_rhs (chrec_type (left), right, at_stmt);
695 0 : return build_polynomial_chrec (CHREC_VARIABLE (chrec_before),
696 0 : left, right);
697 : }
698 :
699 8741780 : default:
700 : /* These nodes do not depend on a loop. */
701 8741780 : if (chrec_before == chrec_dont_know)
702 : return chrec_dont_know;
703 :
704 8722803 : left = chrec_before;
705 8722803 : right = chrec_convert_rhs (chrec_type (left), to_add, at_stmt);
706 : /* When we add the first evolution we need to replace the symbolic
707 : evolution we've put in when the DFS reached the loop PHI node
708 : with the initial value. There's only a limited cases of
709 : extra operations ontop of that symbol allowed, namely
710 : sign-conversions we can look through. For other cases we leave
711 : the symbolic initial condition which causes build_polynomial_chrec
712 : to return chrec_dont_know. See PR42512, PR66375 and PR107176 for
713 : cases we mishandled before. */
714 8722803 : STRIP_NOPS (chrec_before);
715 8722803 : if (chrec_before == gimple_phi_result (loop_phi_node))
716 8722082 : left = fold_convert (TREE_TYPE (left), init_cond);
717 8722803 : return build_polynomial_chrec (loop_nb, left, right);
718 : }
719 : }
720 :
721 : /* Add TO_ADD to the evolution part of CHREC_BEFORE in the dimension
722 : of LOOP_NB.
723 :
724 : Description (provided for completeness, for those who read code in
725 : a plane, and for my poor 62 bytes brain that would have forgotten
726 : all this in the next two or three months):
727 :
728 : The algorithm of translation of programs from the SSA representation
729 : into the chrecs syntax is based on a pattern matching. After having
730 : reconstructed the overall tree expression for a loop, there are only
731 : two cases that can arise:
732 :
733 : 1. a = loop-phi (init, a + expr)
734 : 2. a = loop-phi (init, expr)
735 :
736 : where EXPR is either a scalar constant with respect to the analyzed
737 : loop (this is a degree 0 polynomial), or an expression containing
738 : other loop-phi definitions (these are higher degree polynomials).
739 :
740 : Examples:
741 :
742 : 1.
743 : | init = ...
744 : | loop_1
745 : | a = phi (init, a + 5)
746 : | endloop
747 :
748 : 2.
749 : | inita = ...
750 : | initb = ...
751 : | loop_1
752 : | a = phi (inita, 2 * b + 3)
753 : | b = phi (initb, b + 1)
754 : | endloop
755 :
756 : For the first case, the semantics of the SSA representation is:
757 :
758 : | a (x) = init + \sum_{j = 0}^{x - 1} expr (j)
759 :
760 : that is, there is a loop index "x" that determines the scalar value
761 : of the variable during the loop execution. During the first
762 : iteration, the value is that of the initial condition INIT, while
763 : during the subsequent iterations, it is the sum of the initial
764 : condition with the sum of all the values of EXPR from the initial
765 : iteration to the before last considered iteration.
766 :
767 : For the second case, the semantics of the SSA program is:
768 :
769 : | a (x) = init, if x = 0;
770 : | expr (x - 1), otherwise.
771 :
772 : The second case corresponds to the PEELED_CHREC, whose syntax is
773 : close to the syntax of a loop-phi-node:
774 :
775 : | phi (init, expr) vs. (init, expr)_x
776 :
777 : The proof of the translation algorithm for the first case is a
778 : proof by structural induction based on the degree of EXPR.
779 :
780 : Degree 0:
781 : When EXPR is a constant with respect to the analyzed loop, or in
782 : other words when EXPR is a polynomial of degree 0, the evolution of
783 : the variable A in the loop is an affine function with an initial
784 : condition INIT, and a step EXPR. In order to show this, we start
785 : from the semantics of the SSA representation:
786 :
787 : f (x) = init + \sum_{j = 0}^{x - 1} expr (j)
788 :
789 : and since "expr (j)" is a constant with respect to "j",
790 :
791 : f (x) = init + x * expr
792 :
793 : Finally, based on the semantics of the pure sum chrecs, by
794 : identification we get the corresponding chrecs syntax:
795 :
796 : f (x) = init * \binom{x}{0} + expr * \binom{x}{1}
797 : f (x) -> {init, +, expr}_x
798 :
799 : Higher degree:
800 : Suppose that EXPR is a polynomial of degree N with respect to the
801 : analyzed loop_x for which we have already determined that it is
802 : written under the chrecs syntax:
803 :
804 : | expr (x) -> {b_0, +, b_1, +, ..., +, b_{n-1}} (x)
805 :
806 : We start from the semantics of the SSA program:
807 :
808 : | f (x) = init + \sum_{j = 0}^{x - 1} expr (j)
809 : |
810 : | f (x) = init + \sum_{j = 0}^{x - 1}
811 : | (b_0 * \binom{j}{0} + ... + b_{n-1} * \binom{j}{n-1})
812 : |
813 : | f (x) = init + \sum_{j = 0}^{x - 1}
814 : | \sum_{k = 0}^{n - 1} (b_k * \binom{j}{k})
815 : |
816 : | f (x) = init + \sum_{k = 0}^{n - 1}
817 : | (b_k * \sum_{j = 0}^{x - 1} \binom{j}{k})
818 : |
819 : | f (x) = init + \sum_{k = 0}^{n - 1}
820 : | (b_k * \binom{x}{k + 1})
821 : |
822 : | f (x) = init + b_0 * \binom{x}{1} + ...
823 : | + b_{n-1} * \binom{x}{n}
824 : |
825 : | f (x) = init * \binom{x}{0} + b_0 * \binom{x}{1} + ...
826 : | + b_{n-1} * \binom{x}{n}
827 : |
828 :
829 : And finally from the definition of the chrecs syntax, we identify:
830 : | f (x) -> {init, +, b_0, +, ..., +, b_{n-1}}_x
831 :
832 : This shows the mechanism that stands behind the add_to_evolution
833 : function. An important point is that the use of symbolic
834 : parameters avoids the need of an analysis schedule.
835 :
836 : Example:
837 :
838 : | inita = ...
839 : | initb = ...
840 : | loop_1
841 : | a = phi (inita, a + 2 + b)
842 : | b = phi (initb, b + 1)
843 : | endloop
844 :
845 : When analyzing "a", the algorithm keeps "b" symbolically:
846 :
847 : | a -> {inita, +, 2 + b}_1
848 :
849 : Then, after instantiation, the analyzer ends on the evolution:
850 :
851 : | a -> {inita, +, 2 + initb, +, 1}_1
852 :
853 : */
854 :
855 : tree
856 8898091 : scev_dfs::add_to_evolution (tree chrec_before, enum tree_code code,
857 : tree to_add, gimple *at_stmt)
858 : {
859 8898091 : tree type = chrec_type (to_add);
860 8898091 : tree res = NULL_TREE;
861 :
862 8898091 : if (to_add == NULL_TREE)
863 : return chrec_before;
864 :
865 : /* TO_ADD is either a scalar, or a parameter. TO_ADD is not
866 : instantiated at this point. */
867 8898091 : if (TREE_CODE (to_add) == POLYNOMIAL_CHREC)
868 : /* This should not happen. */
869 0 : return chrec_dont_know;
870 :
871 8898091 : if (dump_file && (dump_flags & TDF_SCEV))
872 : {
873 1 : fprintf (dump_file, "(add_to_evolution \n");
874 1 : fprintf (dump_file, " (loop_nb = %d)\n", loop->num);
875 1 : fprintf (dump_file, " (chrec_before = ");
876 1 : print_generic_expr (dump_file, chrec_before);
877 1 : fprintf (dump_file, ")\n (to_add = ");
878 1 : print_generic_expr (dump_file, to_add);
879 1 : fprintf (dump_file, ")\n");
880 : }
881 :
882 8898091 : if (code == MINUS_EXPR)
883 1603942 : to_add = chrec_fold_multiply (type, to_add, SCALAR_FLOAT_TYPE_P (type)
884 4633 : ? build_real (type, dconstm1)
885 1599309 : : build_int_cst_type (type, -1));
886 :
887 8898091 : res = add_to_evolution_1 (chrec_before, to_add, at_stmt);
888 :
889 8898091 : if (dump_file && (dump_flags & TDF_SCEV))
890 : {
891 1 : fprintf (dump_file, " (res = ");
892 1 : print_generic_expr (dump_file, res);
893 1 : fprintf (dump_file, "))\n");
894 : }
895 :
896 : return res;
897 : }
898 :
899 :
900 : /* Follow the ssa edge into the binary expression RHS0 CODE RHS1.
901 : Return true if the strongly connected component has been found. */
902 :
903 : t_bool
904 1074957 : scev_dfs::follow_ssa_edge_binary (gimple *at_stmt, tree type, tree rhs0,
905 : enum tree_code code, tree rhs1,
906 : tree *evolution_of_loop, int limit)
907 : {
908 1074957 : t_bool res = t_false;
909 1074957 : tree evol;
910 :
911 1074957 : switch (code)
912 : {
913 1068838 : case POINTER_PLUS_EXPR:
914 1068838 : case PLUS_EXPR:
915 1068838 : if (TREE_CODE (rhs0) == SSA_NAME)
916 : {
917 1052037 : if (TREE_CODE (rhs1) == SSA_NAME)
918 : {
919 : /* Match an assignment under the form:
920 : "a = b + c". */
921 :
922 : /* We want only assignments of form "name + name" contribute to
923 : LIMIT, as the other cases do not necessarily contribute to
924 : the complexity of the expression. */
925 1052037 : limit++;
926 :
927 1052037 : evol = *evolution_of_loop;
928 1052037 : res = follow_ssa_edge_expr (at_stmt, rhs0, &evol, limit);
929 1052037 : if (res == t_true)
930 428432 : *evolution_of_loop = add_to_evolution
931 428432 : (chrec_convert (type, evol, at_stmt), code, rhs1, at_stmt);
932 623605 : else if (res == t_false)
933 : {
934 605720 : res = follow_ssa_edge_expr
935 605720 : (at_stmt, rhs1, evolution_of_loop, limit);
936 605720 : if (res == t_true)
937 457095 : *evolution_of_loop = add_to_evolution
938 457095 : (chrec_convert (type, *evolution_of_loop, at_stmt),
939 : code, rhs0, at_stmt);
940 : }
941 : }
942 :
943 : else
944 0 : gcc_unreachable (); /* Handled in caller. */
945 : }
946 :
947 16801 : else if (TREE_CODE (rhs1) == SSA_NAME)
948 : {
949 : /* Match an assignment under the form:
950 : "a = ... + c". */
951 5675 : res = follow_ssa_edge_expr (at_stmt, rhs1, evolution_of_loop, limit);
952 5675 : if (res == t_true)
953 5036 : *evolution_of_loop = add_to_evolution
954 5036 : (chrec_convert (type, *evolution_of_loop, at_stmt),
955 : code, rhs0, at_stmt);
956 : }
957 :
958 : else
959 : /* Otherwise, match an assignment under the form:
960 : "a = ... + ...". */
961 : /* And there is nothing to do. */
962 : res = t_false;
963 : break;
964 :
965 6119 : case MINUS_EXPR:
966 : /* This case is under the form "opnd0 = rhs0 - rhs1". */
967 6119 : if (TREE_CODE (rhs0) == SSA_NAME)
968 0 : gcc_unreachable (); /* Handled in caller. */
969 : else
970 : /* Otherwise, match an assignment under the form:
971 : "a = ... - ...". */
972 : /* And there is nothing to do. */
973 : res = t_false;
974 : break;
975 :
976 : default:
977 : res = t_false;
978 : }
979 :
980 1074957 : return res;
981 : }
982 :
983 : /* Checks whether the I-th argument of a PHI comes from a backedge. */
984 :
985 : static bool
986 8372094 : backedge_phi_arg_p (gphi *phi, int i)
987 : {
988 8372094 : const_edge e = gimple_phi_arg_edge (phi, i);
989 :
990 : /* We would in fact like to test EDGE_DFS_BACK here, but we do not care
991 : about updating it anywhere, and this should work as well most of the
992 : time. */
993 8372094 : if (e->flags & EDGE_IRREDUCIBLE_LOOP)
994 48006 : return true;
995 :
996 : return false;
997 : }
998 :
999 : /* Helper function for one branch of the condition-phi-node. Return
1000 : true if the strongly connected component has been found following
1001 : this path. */
1002 :
1003 : t_bool
1004 3424961 : scev_dfs::follow_ssa_edge_in_condition_phi_branch (int i,
1005 : gphi *condition_phi,
1006 : tree *evolution_of_branch,
1007 : tree init_cond, int limit)
1008 : {
1009 3424961 : tree branch = PHI_ARG_DEF (condition_phi, i);
1010 3424961 : *evolution_of_branch = chrec_dont_know;
1011 :
1012 : /* Do not follow back edges (they must belong to an irreducible loop, which
1013 : we really do not want to worry about). */
1014 3424961 : if (backedge_phi_arg_p (condition_phi, i))
1015 : return t_false;
1016 :
1017 3419341 : if (TREE_CODE (branch) == SSA_NAME)
1018 : {
1019 3185728 : *evolution_of_branch = init_cond;
1020 3185728 : return follow_ssa_edge_expr (condition_phi, branch,
1021 3185728 : evolution_of_branch, limit);
1022 : }
1023 :
1024 : /* This case occurs when one of the condition branches sets
1025 : the variable to a constant: i.e. a phi-node like
1026 : "a_2 = PHI <a_7(5), 2(6)>;".
1027 :
1028 : FIXME: This case have to be refined correctly:
1029 : in some cases it is possible to say something better than
1030 : chrec_dont_know, for example using a wrap-around notation. */
1031 : return t_false;
1032 : }
1033 :
1034 : /* This function merges the branches of a condition-phi-node in a
1035 : loop. */
1036 :
1037 : t_bool
1038 2201061 : scev_dfs::follow_ssa_edge_in_condition_phi (gphi *condition_phi,
1039 : tree *evolution_of_loop, int limit)
1040 : {
1041 2201061 : int i, n;
1042 2201061 : tree init = *evolution_of_loop;
1043 2201061 : tree evolution_of_branch;
1044 2201061 : t_bool res = follow_ssa_edge_in_condition_phi_branch (0, condition_phi,
1045 : &evolution_of_branch,
1046 : init, limit);
1047 2201061 : if (res == t_false || res == t_dont_know)
1048 : return res;
1049 :
1050 1263570 : *evolution_of_loop = evolution_of_branch;
1051 :
1052 1263570 : n = gimple_phi_num_args (condition_phi);
1053 1802396 : for (i = 1; i < n; i++)
1054 : {
1055 : /* Quickly give up when the evolution of one of the branches is
1056 : not known. */
1057 1362935 : if (*evolution_of_loop == chrec_dont_know)
1058 : return t_true;
1059 :
1060 : /* Increase the limit by the PHI argument number to avoid exponential
1061 : time and memory complexity. */
1062 1223900 : res = follow_ssa_edge_in_condition_phi_branch (i, condition_phi,
1063 : &evolution_of_branch,
1064 : init, limit + i);
1065 1223900 : if (res == t_false || res == t_dont_know)
1066 : return res;
1067 :
1068 538826 : *evolution_of_loop = chrec_merge (*evolution_of_loop,
1069 : evolution_of_branch);
1070 : }
1071 :
1072 : return t_true;
1073 : }
1074 :
1075 : /* Follow an SSA edge in an inner loop. It computes the overall
1076 : effect of the loop, and following the symbolic initial conditions,
1077 : it follows the edges in the parent loop. The inner loop is
1078 : considered as a single statement. */
1079 :
1080 : t_bool
1081 251608 : scev_dfs::follow_ssa_edge_inner_loop_phi (gphi *loop_phi_node,
1082 : tree *evolution_of_loop, int limit)
1083 : {
1084 251608 : class loop *loop = loop_containing_stmt (loop_phi_node);
1085 251608 : tree ev = analyze_scalar_evolution (loop, PHI_RESULT (loop_phi_node));
1086 :
1087 : /* Sometimes, the inner loop is too difficult to analyze, and the
1088 : result of the analysis is a symbolic parameter. */
1089 251608 : if (ev == PHI_RESULT (loop_phi_node))
1090 : {
1091 97461 : t_bool res = t_false;
1092 97461 : int i, n = gimple_phi_num_args (loop_phi_node);
1093 :
1094 144744 : for (i = 0; i < n; i++)
1095 : {
1096 136975 : tree arg = PHI_ARG_DEF (loop_phi_node, i);
1097 136975 : basic_block bb;
1098 :
1099 : /* Follow the edges that exit the inner loop. */
1100 136975 : bb = gimple_phi_arg_edge (loop_phi_node, i)->src;
1101 136975 : if (!flow_bb_inside_loop_p (loop, bb))
1102 97461 : res = follow_ssa_edge_expr (loop_phi_node,
1103 : arg, evolution_of_loop, limit);
1104 136975 : if (res == t_true)
1105 : break;
1106 : }
1107 :
1108 : /* If the path crosses this loop-phi, give up. */
1109 97461 : if (res == t_true)
1110 89692 : *evolution_of_loop = chrec_dont_know;
1111 :
1112 97461 : return res;
1113 : }
1114 :
1115 : /* Otherwise, compute the overall effect of the inner loop. */
1116 154147 : ev = compute_overall_effect_of_inner_loop (loop, ev);
1117 154147 : return follow_ssa_edge_expr (loop_phi_node, ev, evolution_of_loop, limit);
1118 : }
1119 :
1120 : /* Follow the ssa edge into the expression EXPR.
1121 : Return true if the strongly connected component has been found. */
1122 :
1123 : t_bool
1124 24349502 : scev_dfs::follow_ssa_edge_expr (gimple *at_stmt, tree expr,
1125 : tree *evolution_of_loop, int limit)
1126 : {
1127 24349502 : gphi *halting_phi = loop_phi_node;
1128 24349502 : enum tree_code code;
1129 24349502 : tree type, rhs0, rhs1 = NULL_TREE;
1130 :
1131 : /* The EXPR is one of the following cases:
1132 : - an SSA_NAME,
1133 : - an INTEGER_CST,
1134 : - a PLUS_EXPR,
1135 : - a POINTER_PLUS_EXPR,
1136 : - a MINUS_EXPR,
1137 : - other cases are not yet handled. */
1138 :
1139 : /* For SSA_NAME look at the definition statement, handling
1140 : PHI nodes and otherwise expand appropriately for the expression
1141 : handling below. */
1142 24349502 : if (TREE_CODE (expr) == SSA_NAME)
1143 : {
1144 24183258 : gimple *def = SSA_NAME_DEF_STMT (expr);
1145 :
1146 24183258 : if (gimple_nop_p (def))
1147 : return t_false;
1148 :
1149 : /* Give up if the path is longer than the MAX that we allow. */
1150 24167276 : if (limit > param_scev_max_expr_complexity)
1151 : {
1152 6252 : *evolution_of_loop = chrec_dont_know;
1153 6252 : return t_dont_know;
1154 : }
1155 :
1156 24161024 : if (gphi *phi = dyn_cast <gphi *>(def))
1157 : {
1158 24892772 : if (!loop_phi_node_p (phi))
1159 : /* DEF is a condition-phi-node. Follow the branches, and
1160 : record their evolutions. Finally, merge the collected
1161 : information and set the approximation to the main
1162 : variable. */
1163 2201061 : return follow_ssa_edge_in_condition_phi (phi, evolution_of_loop,
1164 2201061 : limit);
1165 :
1166 : /* When the analyzed phi is the halting_phi, the
1167 : depth-first search is over: we have found a path from
1168 : the halting_phi to itself in the loop. */
1169 10245325 : if (phi == halting_phi)
1170 : {
1171 9782246 : *evolution_of_loop = expr;
1172 9782246 : return t_true;
1173 : }
1174 :
1175 : /* Otherwise, the evolution of the HALTING_PHI depends
1176 : on the evolution of another loop-phi-node, i.e. the
1177 : evolution function is a higher degree polynomial. */
1178 463079 : class loop *def_loop = loop_containing_stmt (def);
1179 463079 : if (def_loop == loop)
1180 : return t_false;
1181 :
1182 : /* Inner loop. */
1183 273002 : if (flow_loop_nested_p (loop, def_loop))
1184 251608 : return follow_ssa_edge_inner_loop_phi (phi, evolution_of_loop,
1185 251608 : limit + 1);
1186 :
1187 : /* Outer loop. */
1188 : return t_false;
1189 : }
1190 :
1191 : /* At this level of abstraction, the program is just a set
1192 : of GIMPLE_ASSIGNs and PHI_NODEs. In principle there is no
1193 : other def to be handled. */
1194 11714638 : if (!is_gimple_assign (def))
1195 : return t_false;
1196 :
1197 11604859 : code = gimple_assign_rhs_code (def);
1198 11604859 : switch (get_gimple_rhs_class (code))
1199 : {
1200 10070387 : case GIMPLE_BINARY_RHS:
1201 10070387 : rhs0 = gimple_assign_rhs1 (def);
1202 10070387 : rhs1 = gimple_assign_rhs2 (def);
1203 10070387 : break;
1204 1503393 : case GIMPLE_UNARY_RHS:
1205 1503393 : case GIMPLE_SINGLE_RHS:
1206 1503393 : rhs0 = gimple_assign_rhs1 (def);
1207 1503393 : break;
1208 : default:
1209 : return t_false;
1210 : }
1211 11573780 : type = TREE_TYPE (gimple_assign_lhs (def));
1212 11573780 : at_stmt = def;
1213 : }
1214 : else
1215 : {
1216 166244 : code = TREE_CODE (expr);
1217 166244 : type = TREE_TYPE (expr);
1218 : /* Via follow_ssa_edge_inner_loop_phi we arrive here with the
1219 : GENERIC scalar evolution of the inner loop. */
1220 166244 : switch (code)
1221 : {
1222 10732 : CASE_CONVERT:
1223 10732 : rhs0 = TREE_OPERAND (expr, 0);
1224 10732 : break;
1225 22477 : case POINTER_PLUS_EXPR:
1226 22477 : case PLUS_EXPR:
1227 22477 : case MINUS_EXPR:
1228 22477 : rhs0 = TREE_OPERAND (expr, 0);
1229 22477 : rhs1 = TREE_OPERAND (expr, 1);
1230 22477 : STRIP_USELESS_TYPE_CONVERSION (rhs0);
1231 22477 : STRIP_USELESS_TYPE_CONVERSION (rhs1);
1232 22477 : break;
1233 : default:
1234 : rhs0 = expr;
1235 : }
1236 : }
1237 :
1238 11740024 : switch (code)
1239 : {
1240 362338 : CASE_CONVERT:
1241 362338 : {
1242 : /* This assignment is under the form "a_1 = (cast) rhs. We cannot
1243 : validate any precision altering conversion during the SCC
1244 : analysis, so don't even try. */
1245 362338 : if (!tree_nop_conversion_p (type, TREE_TYPE (rhs0)))
1246 : return t_false;
1247 248582 : t_bool res = follow_ssa_edge_expr (at_stmt, rhs0,
1248 : evolution_of_loop, limit);
1249 248582 : if (res == t_true)
1250 99763 : *evolution_of_loop = chrec_convert (type, *evolution_of_loop,
1251 : at_stmt);
1252 : return res;
1253 : }
1254 :
1255 : case INTEGER_CST:
1256 : /* This assignment is under the form "a_1 = 7". */
1257 : return t_false;
1258 :
1259 2192 : case ADDR_EXPR:
1260 2192 : {
1261 : /* Handle &MEM[ptr + CST] which is equivalent to POINTER_PLUS_EXPR. */
1262 2192 : if (TREE_CODE (TREE_OPERAND (rhs0, 0)) != MEM_REF)
1263 : return t_false;
1264 1 : tree mem = TREE_OPERAND (rhs0, 0);
1265 1 : rhs0 = TREE_OPERAND (mem, 0);
1266 1 : rhs1 = TREE_OPERAND (mem, 1);
1267 1 : code = POINTER_PLUS_EXPR;
1268 : }
1269 : /* Fallthru. */
1270 9329837 : case POINTER_PLUS_EXPR:
1271 9329837 : case PLUS_EXPR:
1272 9329837 : case MINUS_EXPR:
1273 : /* This case is under the form "rhs0 +- rhs1". */
1274 9329837 : if (TREE_CODE (rhs0) == SSA_NAME
1275 9306917 : && (TREE_CODE (rhs1) != SSA_NAME || code == MINUS_EXPR))
1276 : {
1277 : /* Match an assignment under the form:
1278 : "a = b +- ...". */
1279 8254880 : t_bool res = follow_ssa_edge_expr (at_stmt, rhs0,
1280 : evolution_of_loop, limit);
1281 8254880 : if (res == t_true)
1282 8007528 : *evolution_of_loop = add_to_evolution
1283 8007528 : (chrec_convert (type, *evolution_of_loop, at_stmt),
1284 : code, rhs1, at_stmt);
1285 8254880 : return res;
1286 : }
1287 : /* Else search for the SCC in both rhs0 and rhs1. */
1288 1074957 : return follow_ssa_edge_binary (at_stmt, type, rhs0, code, rhs1,
1289 1074957 : evolution_of_loop, limit);
1290 :
1291 : default:
1292 : return t_false;
1293 : }
1294 : }
1295 :
1296 :
1297 : /* This section selects the loops that will be good candidates for the
1298 : scalar evolution analysis. For the moment, greedily select all the
1299 : loop nests we could analyze. */
1300 :
1301 : /* For a loop with a single exit edge, return the COND_EXPR that
1302 : guards the exit edge. If the expression is too difficult to
1303 : analyze, then give up. */
1304 :
1305 : gcond *
1306 236 : get_loop_exit_condition (const class loop *loop)
1307 : {
1308 236 : return get_loop_exit_condition (single_exit (loop));
1309 : }
1310 :
1311 : /* If the statement just before the EXIT_EDGE contains a condition then
1312 : return the condition, otherwise NULL. */
1313 :
1314 : gcond *
1315 5087042 : get_loop_exit_condition (const_edge exit_edge)
1316 : {
1317 5087042 : gcond *res = NULL;
1318 :
1319 5087042 : if (dump_file && (dump_flags & TDF_SCEV))
1320 2 : fprintf (dump_file, "(get_loop_exit_condition \n ");
1321 :
1322 5087042 : if (exit_edge)
1323 15261126 : res = safe_dyn_cast <gcond *> (*gsi_last_bb (exit_edge->src));
1324 :
1325 5087042 : if (dump_file && (dump_flags & TDF_SCEV))
1326 : {
1327 2 : print_gimple_stmt (dump_file, res, 0);
1328 2 : fprintf (dump_file, ")\n");
1329 : }
1330 :
1331 5087042 : return res;
1332 : }
1333 :
1334 :
1335 : /* Simplify PEELED_CHREC represented by (init_cond, arg) in LOOP.
1336 : Handle below case and return the corresponding POLYNOMIAL_CHREC:
1337 :
1338 : # i_17 = PHI <i_13(5), 0(3)>
1339 : # _20 = PHI <_5(5), start_4(D)(3)>
1340 : ...
1341 : i_13 = i_17 + 1;
1342 : _5 = start_4(D) + i_13;
1343 :
1344 : Though variable _20 appears as a PEELED_CHREC in the form of
1345 : (start_4, _5)_LOOP, it's a POLYNOMIAL_CHREC like {start_4, 1}_LOOP.
1346 :
1347 : See PR41488. */
1348 :
1349 : static tree
1350 1577480 : simplify_peeled_chrec (class loop *loop, tree arg, tree init_cond)
1351 : {
1352 3154960 : aff_tree aff1, aff2;
1353 1577480 : tree ev, left, right, type, step_val;
1354 1577480 : hash_map<tree, name_expansion *> *peeled_chrec_map = NULL;
1355 :
1356 1577480 : ev = instantiate_parameters (loop, analyze_scalar_evolution (loop, arg));
1357 1577480 : if (ev == NULL_TREE)
1358 0 : return chrec_dont_know;
1359 :
1360 : /* Support the case where we can derive the original CHREC from the
1361 : peeled one if that's a converted other IV. This can be done
1362 : when the original unpeeled converted IV does not overflow and
1363 : has the same initial value. */
1364 1567314 : if (CONVERT_EXPR_P (ev)
1365 10166 : && TREE_CODE (init_cond) == INTEGER_CST
1366 3411 : && TREE_CODE (TREE_OPERAND (ev, 0)) == POLYNOMIAL_CHREC
1367 3142 : && (TYPE_PRECISION (TREE_TYPE (ev))
1368 3142 : > TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (ev, 0))))
1369 1580534 : && (!TYPE_UNSIGNED (TREE_TYPE (ev))
1370 3054 : || TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (ev, 0)))))
1371 : {
1372 3054 : left = CHREC_LEFT (TREE_OPERAND (ev, 0));
1373 3054 : right = CHREC_RIGHT (TREE_OPERAND (ev, 0));
1374 3054 : tree left_before = chrec_fold_minus (TREE_TYPE (TREE_OPERAND (ev, 0)),
1375 : left, right);
1376 3054 : if (TREE_CODE (left_before) == INTEGER_CST
1377 3054 : && wi::to_widest (init_cond) == wi::to_widest (left_before)
1378 6108 : && !scev_probably_wraps_p (NULL_TREE, left_before, right, NULL,
1379 : loop, false))
1380 157 : return build_polynomial_chrec (loop->num, init_cond,
1381 157 : chrec_convert (TREE_TYPE (ev),
1382 : right, NULL,
1383 157 : false, NULL_TREE));
1384 2897 : return chrec_dont_know;
1385 : }
1386 :
1387 1574426 : if (TREE_CODE (ev) != POLYNOMIAL_CHREC)
1388 1534612 : return chrec_dont_know;
1389 :
1390 39814 : left = CHREC_LEFT (ev);
1391 39814 : right = CHREC_RIGHT (ev);
1392 39814 : type = TREE_TYPE (left);
1393 39814 : step_val = chrec_fold_plus (type, init_cond, right);
1394 :
1395 : /* Transform (init, {left, right}_LOOP)_LOOP to {init, right}_LOOP
1396 : if "left" equals to "init + right". */
1397 39814 : if (operand_equal_p (left, step_val, 0))
1398 : {
1399 17822 : if (dump_file && (dump_flags & TDF_SCEV))
1400 1 : fprintf (dump_file, "Simplify PEELED_CHREC into POLYNOMIAL_CHREC.\n");
1401 :
1402 17822 : return build_polynomial_chrec (loop->num, init_cond, right);
1403 : }
1404 :
1405 : /* The affine code only deals with pointer and integer types. */
1406 21992 : if (!POINTER_TYPE_P (type)
1407 16460 : && !INTEGRAL_TYPE_P (type))
1408 15 : return chrec_dont_know;
1409 :
1410 : /* Try harder to check if they are equal. */
1411 21977 : tree_to_aff_combination_expand (left, type, &aff1, &peeled_chrec_map);
1412 21977 : tree_to_aff_combination_expand (step_val, type, &aff2, &peeled_chrec_map);
1413 21977 : free_affine_expand_cache (&peeled_chrec_map);
1414 21977 : aff_combination_scale (&aff2, -1);
1415 21977 : aff_combination_add (&aff1, &aff2);
1416 :
1417 : /* Transform (init, {left, right}_LOOP)_LOOP to {init, right}_LOOP
1418 : if "left" equals to "init + right". */
1419 21977 : if (aff_combination_zero_p (&aff1))
1420 : {
1421 14551 : if (dump_file && (dump_flags & TDF_SCEV))
1422 1 : fprintf (dump_file, "Simplify PEELED_CHREC into POLYNOMIAL_CHREC.\n");
1423 :
1424 14551 : return build_polynomial_chrec (loop->num, init_cond, right);
1425 : }
1426 7426 : return chrec_dont_know;
1427 1577480 : }
1428 :
1429 : /* Given a LOOP_PHI_NODE, this function determines the evolution
1430 : function from LOOP_PHI_NODE to LOOP_PHI_NODE in the loop. */
1431 :
1432 : static tree
1433 10856980 : analyze_evolution_in_loop (gphi *loop_phi_node,
1434 : tree init_cond)
1435 : {
1436 10856980 : int i, n = gimple_phi_num_args (loop_phi_node);
1437 10856980 : tree evolution_function = chrec_not_analyzed_yet;
1438 10856980 : class loop *loop = loop_containing_stmt (loop_phi_node);
1439 10856980 : basic_block bb;
1440 10856980 : static bool simplify_peeled_chrec_p = true;
1441 :
1442 10856980 : if (dump_file && (dump_flags & TDF_SCEV))
1443 : {
1444 3 : fprintf (dump_file, "(analyze_evolution_in_loop \n");
1445 3 : fprintf (dump_file, " (loop_phi_node = ");
1446 3 : print_gimple_stmt (dump_file, loop_phi_node, 0);
1447 3 : fprintf (dump_file, ")\n");
1448 : }
1449 :
1450 28664604 : for (i = 0; i < n; i++)
1451 : {
1452 20418653 : tree arg = PHI_ARG_DEF (loop_phi_node, i);
1453 20418653 : tree ev_fn = chrec_dont_know;
1454 20418653 : t_bool res;
1455 :
1456 : /* Select the edges that enter the loop body. */
1457 20418653 : bb = gimple_phi_arg_edge (loop_phi_node, i)->src;
1458 20418653 : if (!flow_bb_inside_loop_p (loop, bb))
1459 9561673 : continue;
1460 :
1461 10856980 : if (TREE_CODE (arg) == SSA_NAME)
1462 : {
1463 10745272 : bool val = false;
1464 :
1465 : /* Pass in the initial condition to the follow edge function. */
1466 10745272 : scev_dfs dfs (loop, loop_phi_node, init_cond);
1467 10745272 : res = dfs.get_ev (&ev_fn, arg);
1468 :
1469 : /* If ev_fn has no evolution in the inner loop, and the
1470 : init_cond is not equal to ev_fn, then we have an
1471 : ambiguity between two possible values, as we cannot know
1472 : the number of iterations at this point. */
1473 10745272 : if (TREE_CODE (ev_fn) != POLYNOMIAL_CHREC
1474 2483804 : && no_evolution_in_loop_p (ev_fn, loop->num, &val) && val
1475 10745278 : && !operand_equal_p (init_cond, ev_fn, 0))
1476 0 : ev_fn = chrec_dont_know;
1477 : }
1478 : else
1479 : res = t_false;
1480 :
1481 : /* When it is impossible to go back on the same
1482 : loop_phi_node by following the ssa edges, the
1483 : evolution is represented by a peeled chrec, i.e. the
1484 : first iteration, EV_FN has the value INIT_COND, then
1485 : all the other iterations it has the value of ARG.
1486 : For the moment, PEELED_CHREC nodes are not built. */
1487 10745272 : if (res != t_true)
1488 : {
1489 2298634 : ev_fn = chrec_dont_know;
1490 : /* Try to recognize POLYNOMIAL_CHREC which appears in
1491 : the form of PEELED_CHREC, but guard the process with
1492 : a bool variable to keep the analyzer from infinite
1493 : recurrence for real PEELED_RECs. */
1494 2298634 : if (simplify_peeled_chrec_p && TREE_CODE (arg) == SSA_NAME)
1495 : {
1496 1577480 : simplify_peeled_chrec_p = false;
1497 1577480 : ev_fn = simplify_peeled_chrec (loop, arg, init_cond);
1498 1577480 : simplify_peeled_chrec_p = true;
1499 : }
1500 : }
1501 :
1502 : /* When there are multiple back edges of the loop (which in fact never
1503 : happens currently, but nevertheless), merge their evolutions. */
1504 10856980 : evolution_function = chrec_merge (evolution_function, ev_fn);
1505 :
1506 10856980 : if (evolution_function == chrec_dont_know)
1507 : break;
1508 : }
1509 :
1510 10856980 : if (dump_file && (dump_flags & TDF_SCEV))
1511 : {
1512 3 : fprintf (dump_file, " (evolution_function = ");
1513 3 : print_generic_expr (dump_file, evolution_function);
1514 3 : fprintf (dump_file, "))\n");
1515 : }
1516 :
1517 10856980 : return evolution_function;
1518 : }
1519 :
1520 : /* Looks to see if VAR is a copy of a constant (via straightforward assignments
1521 : or degenerate phi's). If so, returns the constant; else, returns VAR. */
1522 :
1523 : static tree
1524 22451648 : follow_copies_to_constant (tree var)
1525 : {
1526 22451648 : tree res = var;
1527 22451648 : while (TREE_CODE (res) == SSA_NAME
1528 : /* We face not updated SSA form in multiple places and this walk
1529 : may end up in sibling loops so we have to guard it. */
1530 27175239 : && !name_registered_for_update_p (res))
1531 : {
1532 16033285 : gimple *def = SSA_NAME_DEF_STMT (res);
1533 16033285 : if (gphi *phi = dyn_cast <gphi *> (def))
1534 : {
1535 4154885 : if (tree rhs = degenerate_phi_result (phi))
1536 : res = rhs;
1537 : else
1538 : break;
1539 : }
1540 11878400 : else if (gimple_assign_single_p (def))
1541 : /* Will exit loop if not an SSA_NAME. */
1542 4397036 : res = gimple_assign_rhs1 (def);
1543 : else
1544 : break;
1545 : }
1546 22451648 : if (CONSTANT_CLASS_P (res))
1547 6596622 : return res;
1548 : return var;
1549 : }
1550 :
1551 : /* Given a loop-phi-node, return the initial conditions of the
1552 : variable on entry of the loop. When the CCP has propagated
1553 : constants into the loop-phi-node, the initial condition is
1554 : instantiated, otherwise the initial condition is kept symbolic.
1555 : This analyzer does not analyze the evolution outside the current
1556 : loop, and leaves this task to the on-demand tree reconstructor. */
1557 :
1558 : static tree
1559 10856980 : analyze_initial_condition (gphi *loop_phi_node)
1560 : {
1561 10856980 : int i, n;
1562 10856980 : tree init_cond = chrec_not_analyzed_yet;
1563 10856980 : class loop *loop = loop_containing_stmt (loop_phi_node);
1564 :
1565 10856980 : if (dump_file && (dump_flags & TDF_SCEV))
1566 : {
1567 3 : fprintf (dump_file, "(analyze_initial_condition \n");
1568 3 : fprintf (dump_file, " (loop_phi_node = \n");
1569 3 : print_gimple_stmt (dump_file, loop_phi_node, 0);
1570 3 : fprintf (dump_file, ")\n");
1571 : }
1572 :
1573 10856980 : n = gimple_phi_num_args (loop_phi_node);
1574 32570940 : for (i = 0; i < n; i++)
1575 : {
1576 21713960 : tree branch = PHI_ARG_DEF (loop_phi_node, i);
1577 21713960 : basic_block bb = gimple_phi_arg_edge (loop_phi_node, i)->src;
1578 :
1579 : /* When the branch is oriented to the loop's body, it does
1580 : not contribute to the initial condition. */
1581 21713960 : if (flow_bb_inside_loop_p (loop, bb))
1582 10856980 : continue;
1583 :
1584 10856980 : if (init_cond == chrec_not_analyzed_yet)
1585 : {
1586 10856980 : init_cond = branch;
1587 10856980 : continue;
1588 : }
1589 :
1590 0 : if (TREE_CODE (branch) == SSA_NAME)
1591 : {
1592 0 : init_cond = chrec_dont_know;
1593 0 : break;
1594 : }
1595 :
1596 0 : init_cond = chrec_merge (init_cond, branch);
1597 : }
1598 :
1599 : /* Ooops -- a loop without an entry??? */
1600 10856980 : if (init_cond == chrec_not_analyzed_yet)
1601 0 : init_cond = chrec_dont_know;
1602 :
1603 : /* We may not have fully constant propagated IL. Handle degenerate PHIs here
1604 : to not miss important early loop unrollings. */
1605 10856980 : init_cond = follow_copies_to_constant (init_cond);
1606 :
1607 10856980 : if (dump_file && (dump_flags & TDF_SCEV))
1608 : {
1609 3 : fprintf (dump_file, " (init_cond = ");
1610 3 : print_generic_expr (dump_file, init_cond);
1611 3 : fprintf (dump_file, "))\n");
1612 : }
1613 :
1614 10856980 : return init_cond;
1615 : }
1616 :
1617 : /* Analyze the scalar evolution for LOOP_PHI_NODE. */
1618 :
1619 : static tree
1620 10856980 : interpret_loop_phi (class loop *loop, gphi *loop_phi_node)
1621 : {
1622 10856980 : class loop *phi_loop = loop_containing_stmt (loop_phi_node);
1623 10856980 : tree init_cond;
1624 :
1625 10856980 : gcc_assert (phi_loop == loop);
1626 :
1627 : /* Otherwise really interpret the loop phi. */
1628 10856980 : init_cond = analyze_initial_condition (loop_phi_node);
1629 10856980 : return analyze_evolution_in_loop (loop_phi_node, init_cond);
1630 : }
1631 :
1632 : /* This function merges the branches of a condition-phi-node,
1633 : contained in the outermost loop, and whose arguments are already
1634 : analyzed. */
1635 :
1636 : static tree
1637 2609822 : interpret_condition_phi (class loop *loop, gphi *condition_phi)
1638 : {
1639 2609822 : int i, n = gimple_phi_num_args (condition_phi);
1640 2609822 : tree res = chrec_not_analyzed_yet;
1641 :
1642 5485204 : for (i = 0; i < n; i++)
1643 : {
1644 4947133 : tree branch_chrec;
1645 :
1646 4947133 : if (backedge_phi_arg_p (condition_phi, i))
1647 : {
1648 42386 : res = chrec_dont_know;
1649 42386 : break;
1650 : }
1651 :
1652 4904747 : branch_chrec = analyze_scalar_evolution
1653 4904747 : (loop, PHI_ARG_DEF (condition_phi, i));
1654 :
1655 4904747 : res = chrec_merge (res, branch_chrec);
1656 4904747 : if (res == chrec_dont_know)
1657 : break;
1658 : }
1659 :
1660 2609822 : return res;
1661 : }
1662 :
1663 : /* Interpret the operation RHS1 OP RHS2. If we didn't
1664 : analyze this node before, follow the definitions until ending
1665 : either on an analyzed GIMPLE_ASSIGN, or on a loop-phi-node. On the
1666 : return path, this function propagates evolutions (ala constant copy
1667 : propagation). OPND1 is not a GIMPLE expression because we could
1668 : analyze the effect of an inner loop: see interpret_loop_phi. */
1669 :
1670 : static tree
1671 44572356 : interpret_rhs_expr (class loop *loop, gimple *at_stmt,
1672 : tree type, tree rhs1, enum tree_code code, tree rhs2)
1673 : {
1674 44572356 : tree res, chrec1, chrec2, ctype;
1675 44572356 : gimple *def;
1676 :
1677 44572356 : if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS)
1678 : {
1679 10799141 : if (is_gimple_min_invariant (rhs1))
1680 2437124 : return chrec_convert (type, rhs1, at_stmt);
1681 :
1682 8362017 : if (code == SSA_NAME)
1683 131100 : return chrec_convert (type, analyze_scalar_evolution (loop, rhs1),
1684 131100 : at_stmt);
1685 : }
1686 :
1687 42004132 : switch (code)
1688 : {
1689 340350 : case ADDR_EXPR:
1690 340350 : if (TREE_CODE (TREE_OPERAND (rhs1, 0)) == MEM_REF
1691 340350 : || handled_component_p (TREE_OPERAND (rhs1, 0)))
1692 : {
1693 340093 : machine_mode mode;
1694 340093 : poly_int64 bitsize, bitpos;
1695 340093 : int unsignedp, reversep;
1696 340093 : int volatilep = 0;
1697 340093 : tree base, offset;
1698 340093 : tree chrec3;
1699 340093 : tree unitpos;
1700 :
1701 340093 : base = get_inner_reference (TREE_OPERAND (rhs1, 0),
1702 : &bitsize, &bitpos, &offset, &mode,
1703 : &unsignedp, &reversep, &volatilep);
1704 :
1705 340093 : if (TREE_CODE (base) == MEM_REF)
1706 : {
1707 261067 : rhs2 = TREE_OPERAND (base, 1);
1708 261067 : rhs1 = TREE_OPERAND (base, 0);
1709 :
1710 261067 : chrec1 = analyze_scalar_evolution (loop, rhs1);
1711 261067 : chrec2 = analyze_scalar_evolution (loop, rhs2);
1712 261067 : chrec1 = chrec_convert (type, chrec1, at_stmt);
1713 261067 : chrec2 = chrec_convert (TREE_TYPE (rhs2), chrec2, at_stmt);
1714 261067 : chrec1 = instantiate_parameters (loop, chrec1);
1715 261067 : chrec2 = instantiate_parameters (loop, chrec2);
1716 261067 : res = chrec_fold_plus (type, chrec1, chrec2);
1717 : }
1718 : else
1719 : {
1720 79026 : chrec1 = analyze_scalar_evolution_for_address_of (loop, base);
1721 79026 : chrec1 = chrec_convert (type, chrec1, at_stmt);
1722 79026 : res = chrec1;
1723 : }
1724 :
1725 340093 : if (offset != NULL_TREE)
1726 : {
1727 150118 : chrec2 = analyze_scalar_evolution (loop, offset);
1728 150118 : chrec2 = chrec_convert (TREE_TYPE (offset), chrec2, at_stmt);
1729 150118 : chrec2 = instantiate_parameters (loop, chrec2);
1730 150118 : res = chrec_fold_plus (type, res, chrec2);
1731 : }
1732 :
1733 340093 : if (maybe_ne (bitpos, 0))
1734 : {
1735 126446 : unitpos = size_int (exact_div (bitpos, BITS_PER_UNIT));
1736 126446 : chrec3 = analyze_scalar_evolution (loop, unitpos);
1737 126446 : chrec3 = chrec_convert (TREE_TYPE (unitpos), chrec3, at_stmt);
1738 126446 : chrec3 = instantiate_parameters (loop, chrec3);
1739 126446 : res = chrec_fold_plus (type, res, chrec3);
1740 : }
1741 : }
1742 : else
1743 257 : res = chrec_dont_know;
1744 : break;
1745 :
1746 3462701 : case POINTER_PLUS_EXPR:
1747 3462701 : chrec1 = analyze_scalar_evolution (loop, rhs1);
1748 3462701 : chrec2 = analyze_scalar_evolution (loop, rhs2);
1749 3462701 : chrec1 = chrec_convert (type, chrec1, at_stmt);
1750 3462701 : chrec2 = chrec_convert (TREE_TYPE (rhs2), chrec2, at_stmt);
1751 3462701 : chrec1 = instantiate_parameters (loop, chrec1);
1752 3462701 : chrec2 = instantiate_parameters (loop, chrec2);
1753 3462701 : res = chrec_fold_plus (type, chrec1, chrec2);
1754 3462701 : break;
1755 :
1756 126216 : case POINTER_DIFF_EXPR:
1757 126216 : {
1758 126216 : tree utype = unsigned_type_for (type);
1759 126216 : chrec1 = analyze_scalar_evolution (loop, rhs1);
1760 126216 : chrec2 = analyze_scalar_evolution (loop, rhs2);
1761 126216 : chrec1 = chrec_convert (utype, chrec1, at_stmt);
1762 126216 : chrec2 = chrec_convert (utype, chrec2, at_stmt);
1763 126216 : chrec1 = instantiate_parameters (loop, chrec1);
1764 126216 : chrec2 = instantiate_parameters (loop, chrec2);
1765 126216 : res = chrec_fold_minus (utype, chrec1, chrec2);
1766 126216 : res = chrec_convert (type, res, at_stmt);
1767 126216 : break;
1768 : }
1769 :
1770 11757000 : case PLUS_EXPR:
1771 11757000 : chrec1 = analyze_scalar_evolution (loop, rhs1);
1772 11757000 : chrec2 = analyze_scalar_evolution (loop, rhs2);
1773 11757000 : ctype = type;
1774 : /* When the stmt is conditionally executed re-write the CHREC
1775 : into a form that has well-defined behavior on overflow. */
1776 11757000 : if (at_stmt
1777 10635951 : && INTEGRAL_TYPE_P (type)
1778 10541604 : && ! TYPE_OVERFLOW_WRAPS (type)
1779 19803539 : && ! dominated_by_p (CDI_DOMINATORS, loop->latch,
1780 8046539 : gimple_bb (at_stmt)))
1781 703279 : ctype = unsigned_type_for (type);
1782 11757000 : chrec1 = chrec_convert (ctype, chrec1, at_stmt);
1783 11757000 : chrec2 = chrec_convert (ctype, chrec2, at_stmt);
1784 11757000 : chrec1 = instantiate_parameters (loop, chrec1);
1785 11757000 : chrec2 = instantiate_parameters (loop, chrec2);
1786 11757000 : res = chrec_fold_plus (ctype, chrec1, chrec2);
1787 11757000 : if (type != ctype)
1788 703279 : res = chrec_convert (type, res, at_stmt);
1789 : break;
1790 :
1791 1469289 : case MINUS_EXPR:
1792 1469289 : chrec1 = analyze_scalar_evolution (loop, rhs1);
1793 1469289 : chrec2 = analyze_scalar_evolution (loop, rhs2);
1794 1469289 : ctype = type;
1795 : /* When the stmt is conditionally executed re-write the CHREC
1796 : into a form that has well-defined behavior on overflow. */
1797 1469289 : if (at_stmt
1798 1405442 : && INTEGRAL_TYPE_P (type)
1799 1368810 : && ! TYPE_OVERFLOW_WRAPS (type)
1800 1999420 : && ! dominated_by_p (CDI_DOMINATORS,
1801 530131 : loop->latch, gimple_bb (at_stmt)))
1802 132756 : ctype = unsigned_type_for (type);
1803 1469289 : chrec1 = chrec_convert (ctype, chrec1, at_stmt);
1804 1469289 : chrec2 = chrec_convert (ctype, chrec2, at_stmt);
1805 1469289 : chrec1 = instantiate_parameters (loop, chrec1);
1806 1469289 : chrec2 = instantiate_parameters (loop, chrec2);
1807 1469289 : res = chrec_fold_minus (ctype, chrec1, chrec2);
1808 1469289 : if (type != ctype)
1809 132756 : res = chrec_convert (type, res, at_stmt);
1810 : break;
1811 :
1812 81784 : case NEGATE_EXPR:
1813 81784 : chrec1 = analyze_scalar_evolution (loop, rhs1);
1814 81784 : ctype = type;
1815 : /* When the stmt is conditionally executed re-write the CHREC
1816 : into a form that has well-defined behavior on overflow. */
1817 81784 : if (at_stmt
1818 70447 : && INTEGRAL_TYPE_P (type)
1819 68667 : && ! TYPE_OVERFLOW_WRAPS (type)
1820 120083 : && ! dominated_by_p (CDI_DOMINATORS,
1821 38299 : loop->latch, gimple_bb (at_stmt)))
1822 7632 : ctype = unsigned_type_for (type);
1823 81784 : chrec1 = chrec_convert (ctype, chrec1, at_stmt);
1824 : /* TYPE may be integer, real or complex, so use fold_convert. */
1825 81784 : chrec1 = instantiate_parameters (loop, chrec1);
1826 81784 : res = chrec_fold_multiply (ctype, chrec1,
1827 : fold_convert (ctype, integer_minus_one_node));
1828 81784 : if (type != ctype)
1829 7632 : res = chrec_convert (type, res, at_stmt);
1830 : break;
1831 :
1832 34976 : case BIT_NOT_EXPR:
1833 : /* Handle ~X as -1 - X. */
1834 34976 : chrec1 = analyze_scalar_evolution (loop, rhs1);
1835 34976 : chrec1 = chrec_convert (type, chrec1, at_stmt);
1836 34976 : chrec1 = instantiate_parameters (loop, chrec1);
1837 34976 : res = chrec_fold_minus (type,
1838 : fold_convert (type, integer_minus_one_node),
1839 : chrec1);
1840 34976 : break;
1841 :
1842 6056166 : case MULT_EXPR:
1843 6056166 : chrec1 = analyze_scalar_evolution (loop, rhs1);
1844 6056166 : chrec2 = analyze_scalar_evolution (loop, rhs2);
1845 6056166 : ctype = type;
1846 : /* When the stmt is conditionally executed re-write the CHREC
1847 : into a form that has well-defined behavior on overflow. */
1848 6056166 : if (at_stmt
1849 4144698 : && INTEGRAL_TYPE_P (type)
1850 4034057 : && ! TYPE_OVERFLOW_WRAPS (type)
1851 7873550 : && ! dominated_by_p (CDI_DOMINATORS,
1852 1817384 : loop->latch, gimple_bb (at_stmt)))
1853 161304 : ctype = unsigned_type_for (type);
1854 6056166 : chrec1 = chrec_convert (ctype, chrec1, at_stmt);
1855 6056166 : chrec2 = chrec_convert (ctype, chrec2, at_stmt);
1856 6056166 : chrec1 = instantiate_parameters (loop, chrec1);
1857 6056166 : chrec2 = instantiate_parameters (loop, chrec2);
1858 6056166 : res = chrec_fold_multiply (ctype, chrec1, chrec2);
1859 6056166 : if (type != ctype)
1860 161304 : res = chrec_convert (type, res, at_stmt);
1861 : break;
1862 :
1863 154626 : case LSHIFT_EXPR:
1864 154626 : {
1865 : /* Handle A<<B as A * (1<<B). */
1866 154626 : tree uns = unsigned_type_for (type);
1867 154626 : chrec1 = analyze_scalar_evolution (loop, rhs1);
1868 154626 : chrec2 = analyze_scalar_evolution (loop, rhs2);
1869 154626 : chrec1 = chrec_convert (uns, chrec1, at_stmt);
1870 154626 : chrec1 = instantiate_parameters (loop, chrec1);
1871 154626 : chrec2 = instantiate_parameters (loop, chrec2);
1872 :
1873 154626 : tree one = build_int_cst (uns, 1);
1874 154626 : chrec2 = fold_build2 (LSHIFT_EXPR, uns, one, chrec2);
1875 154626 : res = chrec_fold_multiply (uns, chrec1, chrec2);
1876 154626 : res = chrec_convert (type, res, at_stmt);
1877 : }
1878 154626 : break;
1879 :
1880 8434512 : CASE_CONVERT:
1881 : /* In case we have a truncation of a widened operation that in
1882 : the truncated type has undefined overflow behavior analyze
1883 : the operation done in an unsigned type of the same precision
1884 : as the final truncation. We cannot derive a scalar evolution
1885 : for the widened operation but for the truncated result. */
1886 8434512 : if (TREE_CODE (type) == INTEGER_TYPE
1887 8142139 : && TREE_CODE (TREE_TYPE (rhs1)) == INTEGER_TYPE
1888 7616151 : && TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (rhs1))
1889 458062 : && TYPE_OVERFLOW_UNDEFINED (type)
1890 268033 : && TREE_CODE (rhs1) == SSA_NAME
1891 267865 : && (def = SSA_NAME_DEF_STMT (rhs1))
1892 267865 : && is_gimple_assign (def)
1893 173392 : && TREE_CODE_CLASS (gimple_assign_rhs_code (def)) == tcc_binary
1894 8555493 : && TREE_CODE (gimple_assign_rhs2 (def)) == INTEGER_CST)
1895 : {
1896 88152 : tree utype = unsigned_type_for (type);
1897 88152 : chrec1 = interpret_rhs_expr (loop, at_stmt, utype,
1898 : gimple_assign_rhs1 (def),
1899 : gimple_assign_rhs_code (def),
1900 : gimple_assign_rhs2 (def));
1901 : }
1902 : else
1903 8346360 : chrec1 = analyze_scalar_evolution (loop, rhs1);
1904 8434512 : res = chrec_convert (type, chrec1, at_stmt, true, rhs1);
1905 8434512 : break;
1906 :
1907 390235 : case BIT_AND_EXPR:
1908 : /* Given int variable A, handle A&0xffff as (int)(unsigned short)A.
1909 : If A is SCEV and its value is in the range of representable set
1910 : of type unsigned short, the result expression is a (no-overflow)
1911 : SCEV. */
1912 390235 : res = chrec_dont_know;
1913 390235 : if (tree_fits_uhwi_p (rhs2))
1914 : {
1915 265745 : int precision;
1916 265745 : unsigned HOST_WIDE_INT val = tree_to_uhwi (rhs2);
1917 :
1918 265745 : val ++;
1919 : /* Skip if value of rhs2 wraps in unsigned HOST_WIDE_INT or
1920 : it's not the maximum value of a smaller type than rhs1. */
1921 265745 : if (val != 0
1922 209543 : && (precision = exact_log2 (val)) > 0
1923 475288 : && (unsigned) precision < TYPE_PRECISION (TREE_TYPE (rhs1)))
1924 : {
1925 209543 : tree utype = build_nonstandard_integer_type (precision, 1);
1926 :
1927 209543 : if (TYPE_PRECISION (utype) < TYPE_PRECISION (TREE_TYPE (rhs1)))
1928 : {
1929 209543 : chrec1 = analyze_scalar_evolution (loop, rhs1);
1930 209543 : chrec1 = chrec_convert (utype, chrec1, at_stmt);
1931 209543 : res = chrec_convert (TREE_TYPE (rhs1), chrec1, at_stmt);
1932 : }
1933 : }
1934 : }
1935 : break;
1936 :
1937 9696277 : default:
1938 9696277 : res = chrec_dont_know;
1939 9696277 : break;
1940 : }
1941 :
1942 : return res;
1943 : }
1944 :
1945 : /* Interpret the expression EXPR. */
1946 :
1947 : static tree
1948 8829411 : interpret_expr (class loop *loop, gimple *at_stmt, tree expr)
1949 : {
1950 8829411 : enum tree_code code;
1951 8829411 : tree type = TREE_TYPE (expr), op0, op1;
1952 :
1953 8829411 : if (automatically_generated_chrec_p (expr))
1954 : return expr;
1955 :
1956 8824592 : if (TREE_CODE (expr) == POLYNOMIAL_CHREC
1957 8824104 : || TREE_CODE (expr) == CALL_EXPR
1958 17648628 : || get_gimple_rhs_class (TREE_CODE (expr)) == GIMPLE_TERNARY_RHS)
1959 : return chrec_dont_know;
1960 :
1961 8754159 : extract_ops_from_tree (expr, &code, &op0, &op1);
1962 :
1963 8754159 : return interpret_rhs_expr (loop, at_stmt, type,
1964 8754159 : op0, code, op1);
1965 : }
1966 :
1967 : /* Interpret the rhs of the assignment STMT. */
1968 :
1969 : static tree
1970 35730045 : interpret_gimple_assign (class loop *loop, gimple *stmt)
1971 : {
1972 35730045 : tree type = TREE_TYPE (gimple_assign_lhs (stmt));
1973 35730045 : enum tree_code code = gimple_assign_rhs_code (stmt);
1974 :
1975 35730045 : return interpret_rhs_expr (loop, stmt, type,
1976 : gimple_assign_rhs1 (stmt), code,
1977 35730045 : gimple_assign_rhs2 (stmt));
1978 : }
1979 :
1980 :
1981 :
1982 : /* This section contains all the entry points:
1983 : - number_of_iterations_in_loop,
1984 : - analyze_scalar_evolution,
1985 : - instantiate_parameters.
1986 : */
1987 :
1988 : /* Helper recursive function. */
1989 :
1990 : static tree
1991 74116236 : analyze_scalar_evolution_1 (class loop *loop, tree var)
1992 : {
1993 74116236 : gimple *def;
1994 74116236 : basic_block bb;
1995 74116236 : class loop *def_loop;
1996 74116236 : tree res;
1997 :
1998 74116236 : if (TREE_CODE (var) != SSA_NAME)
1999 8829411 : return interpret_expr (loop, NULL, var);
2000 :
2001 65286825 : def = SSA_NAME_DEF_STMT (var);
2002 65286825 : bb = gimple_bb (def);
2003 65286825 : def_loop = bb->loop_father;
2004 :
2005 65286825 : if (!flow_bb_inside_loop_p (loop, bb))
2006 : {
2007 : /* Keep symbolic form, but look through obvious copies for constants. */
2008 11594668 : res = follow_copies_to_constant (var);
2009 11594668 : goto set_and_end;
2010 : }
2011 :
2012 53692157 : if (loop != def_loop)
2013 : {
2014 3925177 : res = analyze_scalar_evolution_1 (def_loop, var);
2015 3925177 : class loop *loop_to_skip = superloop_at_depth (def_loop,
2016 3925177 : loop_depth (loop) + 1);
2017 3925177 : res = compute_overall_effect_of_inner_loop (loop_to_skip, res);
2018 3925177 : if (chrec_contains_symbols_defined_in_loop (res, loop->num))
2019 294668 : res = analyze_scalar_evolution_1 (loop, res);
2020 3925177 : goto set_and_end;
2021 : }
2022 :
2023 49766980 : switch (gimple_code (def))
2024 : {
2025 35730045 : case GIMPLE_ASSIGN:
2026 35730045 : res = interpret_gimple_assign (loop, def);
2027 35730045 : break;
2028 :
2029 13466802 : case GIMPLE_PHI:
2030 26933604 : if (loop_phi_node_p (def))
2031 10856980 : res = interpret_loop_phi (loop, as_a <gphi *> (def));
2032 : else
2033 2609822 : res = interpret_condition_phi (loop, as_a <gphi *> (def));
2034 : break;
2035 :
2036 570133 : default:
2037 570133 : res = chrec_dont_know;
2038 570133 : break;
2039 : }
2040 :
2041 65286825 : set_and_end:
2042 :
2043 : /* Keep the symbolic form. */
2044 65286825 : if (res == chrec_dont_know)
2045 23962632 : res = var;
2046 :
2047 65286825 : if (loop == def_loop)
2048 49766980 : set_scalar_evolution (block_before_loop (loop), var, res);
2049 :
2050 : return res;
2051 : }
2052 :
2053 : /* Analyzes and returns the scalar evolution of the ssa_name VAR in
2054 : LOOP. LOOP is the loop in which the variable is used.
2055 :
2056 : Example of use: having a pointer VAR to a SSA_NAME node, STMT a
2057 : pointer to the statement that uses this variable, in order to
2058 : determine the evolution function of the variable, use the following
2059 : calls:
2060 :
2061 : loop_p loop = loop_containing_stmt (stmt);
2062 : tree chrec_with_symbols = analyze_scalar_evolution (loop, var);
2063 : tree chrec_instantiated = instantiate_parameters (loop, chrec_with_symbols);
2064 : */
2065 :
2066 : tree
2067 193786106 : analyze_scalar_evolution (class loop *loop, tree var)
2068 : {
2069 193786106 : tree res;
2070 :
2071 : /* ??? Fix callers. */
2072 193786106 : if (! loop)
2073 : return var;
2074 :
2075 193628608 : if (dump_file && (dump_flags & TDF_SCEV))
2076 : {
2077 36 : fprintf (dump_file, "(analyze_scalar_evolution \n");
2078 36 : fprintf (dump_file, " (loop_nb = %d)\n", loop->num);
2079 36 : fprintf (dump_file, " (scalar = ");
2080 36 : print_generic_expr (dump_file, var);
2081 36 : fprintf (dump_file, ")\n");
2082 : }
2083 :
2084 193628608 : res = get_scalar_evolution (block_before_loop (loop), var);
2085 193628608 : if (res == chrec_not_analyzed_yet)
2086 : {
2087 : /* We'll recurse into instantiate_scev, avoid tearing down the
2088 : instantiate cache repeatedly and keep it live from here. */
2089 69896391 : bool destr = false;
2090 69896391 : if (!global_cache)
2091 : {
2092 41859506 : global_cache = new instantiate_cache_type;
2093 41859506 : destr = true;
2094 : }
2095 69896391 : res = analyze_scalar_evolution_1 (loop, var);
2096 69896391 : if (destr)
2097 : {
2098 41859506 : delete global_cache;
2099 41859506 : global_cache = NULL;
2100 : }
2101 : }
2102 :
2103 193628608 : if (dump_file && (dump_flags & TDF_SCEV))
2104 36 : fprintf (dump_file, ")\n");
2105 :
2106 : return res;
2107 : }
2108 :
2109 : /* If CHREC doesn't overflow, set the nonwrapping flag. */
2110 :
2111 10632690 : void record_nonwrapping_chrec (tree chrec)
2112 : {
2113 10632690 : CHREC_NOWRAP(chrec) = 1;
2114 :
2115 10632690 : if (dump_file && (dump_flags & TDF_SCEV))
2116 : {
2117 6 : fprintf (dump_file, "(record_nonwrapping_chrec: ");
2118 6 : print_generic_expr (dump_file, chrec);
2119 6 : fprintf (dump_file, ")\n");
2120 : }
2121 10632690 : }
2122 :
2123 : /* Return true if CHREC's nonwrapping flag is set. */
2124 :
2125 220297 : bool nonwrapping_chrec_p (tree chrec)
2126 : {
2127 220297 : if (!chrec || TREE_CODE(chrec) != POLYNOMIAL_CHREC)
2128 : return false;
2129 :
2130 220297 : return CHREC_NOWRAP(chrec);
2131 : }
2132 :
2133 : /* Analyzes and returns the scalar evolution of VAR address in LOOP. */
2134 :
2135 : static tree
2136 79026 : analyze_scalar_evolution_for_address_of (class loop *loop, tree var)
2137 : {
2138 79026 : return analyze_scalar_evolution (loop, build_fold_addr_expr (var));
2139 : }
2140 :
2141 : /* Analyze scalar evolution of use of VERSION in USE_LOOP with respect to
2142 : WRTO_LOOP (which should be a superloop of USE_LOOP)
2143 :
2144 : FOLDED_CASTS is set to true if resolve_mixers used
2145 : chrec_convert_aggressive (TODO -- not really, we are way too conservative
2146 : at the moment in order to keep things simple).
2147 :
2148 : To illustrate the meaning of USE_LOOP and WRTO_LOOP, consider the following
2149 : example:
2150 :
2151 : for (i = 0; i < 100; i++) -- loop 1
2152 : {
2153 : for (j = 0; j < 100; j++) -- loop 2
2154 : {
2155 : k1 = i;
2156 : k2 = j;
2157 :
2158 : use2 (k1, k2);
2159 :
2160 : for (t = 0; t < 100; t++) -- loop 3
2161 : use3 (k1, k2);
2162 :
2163 : }
2164 : use1 (k1, k2);
2165 : }
2166 :
2167 : Both k1 and k2 are invariants in loop3, thus
2168 : analyze_scalar_evolution_in_loop (loop3, loop3, k1) = k1
2169 : analyze_scalar_evolution_in_loop (loop3, loop3, k2) = k2
2170 :
2171 : As they are invariant, it does not matter whether we consider their
2172 : usage in loop 3 or loop 2, hence
2173 : analyze_scalar_evolution_in_loop (loop2, loop3, k1) =
2174 : analyze_scalar_evolution_in_loop (loop2, loop2, k1) = i
2175 : analyze_scalar_evolution_in_loop (loop2, loop3, k2) =
2176 : analyze_scalar_evolution_in_loop (loop2, loop2, k2) = [0,+,1]_2
2177 :
2178 : Similarly for their evolutions with respect to loop 1. The values of K2
2179 : in the use in loop 2 vary independently on loop 1, thus we cannot express
2180 : the evolution with respect to loop 1:
2181 : analyze_scalar_evolution_in_loop (loop1, loop3, k1) =
2182 : analyze_scalar_evolution_in_loop (loop1, loop2, k1) = [0,+,1]_1
2183 : analyze_scalar_evolution_in_loop (loop1, loop3, k2) =
2184 : analyze_scalar_evolution_in_loop (loop1, loop2, k2) = dont_know
2185 :
2186 : The value of k2 in the use in loop 1 is known, though:
2187 : analyze_scalar_evolution_in_loop (loop1, loop1, k1) = [0,+,1]_1
2188 : analyze_scalar_evolution_in_loop (loop1, loop1, k2) = 100
2189 : */
2190 :
2191 : static tree
2192 49445930 : analyze_scalar_evolution_in_loop (class loop *wrto_loop, class loop *use_loop,
2193 : tree version, bool *folded_casts)
2194 : {
2195 49445930 : bool val = false;
2196 49445930 : tree ev = version, tmp;
2197 :
2198 : /* We cannot just do
2199 :
2200 : tmp = analyze_scalar_evolution (use_loop, version);
2201 : ev = resolve_mixers (wrto_loop, tmp, folded_casts);
2202 :
2203 : as resolve_mixers would query the scalar evolution with respect to
2204 : wrto_loop. For example, in the situation described in the function
2205 : comment, suppose that wrto_loop = loop1, use_loop = loop3 and
2206 : version = k2. Then
2207 :
2208 : analyze_scalar_evolution (use_loop, version) = k2
2209 :
2210 : and resolve_mixers (loop1, k2, folded_casts) finds that the value of
2211 : k2 in loop 1 is 100, which is a wrong result, since we are interested
2212 : in the value in loop 3.
2213 :
2214 : Instead, we need to proceed from use_loop to wrto_loop loop by loop,
2215 : each time checking that there is no evolution in the inner loop. */
2216 :
2217 49445930 : if (folded_casts)
2218 49445930 : *folded_casts = false;
2219 51748218 : while (1)
2220 : {
2221 50597074 : tmp = analyze_scalar_evolution (use_loop, ev);
2222 50597074 : ev = resolve_mixers (use_loop, tmp, folded_casts);
2223 :
2224 50597074 : if (use_loop == wrto_loop)
2225 : return ev;
2226 :
2227 : /* If the value of the use changes in the inner loop, we cannot express
2228 : its value in the outer loop (we might try to return interval chrec,
2229 : but we do not have a user for it anyway) */
2230 4301042 : if (!no_evolution_in_loop_p (ev, use_loop->num, &val)
2231 4301042 : || !val)
2232 3149898 : return chrec_dont_know;
2233 :
2234 1151144 : use_loop = loop_outer (use_loop);
2235 : }
2236 : }
2237 :
2238 :
2239 : /* Computes a hash function for database element ELT. */
2240 :
2241 : static inline hashval_t
2242 267221 : hash_idx_scev_info (const void *elt_)
2243 : {
2244 267221 : unsigned idx = ((size_t) elt_) - 2;
2245 267221 : return scev_info_hasher::hash (&global_cache->entries[idx]);
2246 : }
2247 :
2248 : /* Compares database elements E1 and E2. */
2249 :
2250 : static inline int
2251 31700914 : eq_idx_scev_info (const void *e1, const void *e2)
2252 : {
2253 31700914 : unsigned idx1 = ((size_t) e1) - 2;
2254 31700914 : return scev_info_hasher::equal (&global_cache->entries[idx1],
2255 31700914 : (const scev_info_str *) e2);
2256 : }
2257 :
2258 : /* Returns from CACHE the slot number of the cached chrec for NAME. */
2259 :
2260 : static unsigned
2261 63374810 : get_instantiated_value_entry (instantiate_cache_type &cache,
2262 : tree name, edge instantiate_below)
2263 : {
2264 63374810 : if (!cache.map)
2265 : {
2266 29107200 : cache.map = htab_create (10, hash_idx_scev_info, eq_idx_scev_info, NULL);
2267 29107200 : cache.entries.create (10);
2268 : }
2269 :
2270 63374810 : scev_info_str e;
2271 63374810 : e.name_version = SSA_NAME_VERSION (name);
2272 63374810 : e.instantiated_below = instantiate_below->dest->index;
2273 63374810 : void **slot = htab_find_slot_with_hash (cache.map, &e,
2274 : scev_info_hasher::hash (&e), INSERT);
2275 63374810 : if (!*slot)
2276 : {
2277 32779702 : e.chrec = chrec_not_analyzed_yet;
2278 32779702 : *slot = (void *)(size_t)(cache.entries.length () + 2);
2279 32779702 : cache.entries.safe_push (e);
2280 : }
2281 :
2282 63374810 : return ((size_t)*slot) - 2;
2283 : }
2284 :
2285 :
2286 : /* Return the closed_loop_phi node for VAR. If there is none, return
2287 : NULL_TREE. */
2288 :
2289 : static tree
2290 1880590 : loop_closed_phi_def (tree var)
2291 : {
2292 1880590 : class loop *loop;
2293 1880590 : edge exit;
2294 1880590 : gphi *phi;
2295 1880590 : gphi_iterator psi;
2296 :
2297 1880590 : if (var == NULL_TREE
2298 1880590 : || TREE_CODE (var) != SSA_NAME)
2299 : return NULL_TREE;
2300 :
2301 1880590 : loop = loop_containing_stmt (SSA_NAME_DEF_STMT (var));
2302 1880590 : exit = single_exit (loop);
2303 1880590 : if (!exit)
2304 : return NULL_TREE;
2305 :
2306 1574133 : for (psi = gsi_start_phis (exit->dest); !gsi_end_p (psi); gsi_next (&psi))
2307 : {
2308 964834 : phi = psi.phi ();
2309 964834 : if (PHI_ARG_DEF_FROM_EDGE (phi, exit) == var)
2310 261723 : return PHI_RESULT (phi);
2311 : }
2312 :
2313 : return NULL_TREE;
2314 : }
2315 :
2316 : static tree instantiate_scev_r (edge, class loop *, class loop *,
2317 : tree, bool *, int);
2318 :
2319 : /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW
2320 : and EVOLUTION_LOOP, that were left under a symbolic form.
2321 :
2322 : CHREC is an SSA_NAME to be instantiated.
2323 :
2324 : CACHE is the cache of already instantiated values.
2325 :
2326 : Variable pointed by FOLD_CONVERSIONS is set to TRUE when the
2327 : conversions that may wrap in signed/pointer type are folded, as long
2328 : as the value of the chrec is preserved. If FOLD_CONVERSIONS is NULL
2329 : then we don't do such fold.
2330 :
2331 : SIZE_EXPR is used for computing the size of the expression to be
2332 : instantiated, and to stop if it exceeds some limit. */
2333 :
2334 : static tree
2335 110875149 : instantiate_scev_name (edge instantiate_below,
2336 : class loop *evolution_loop, class loop *inner_loop,
2337 : tree chrec,
2338 : bool *fold_conversions,
2339 : int size_expr)
2340 : {
2341 110875149 : tree res;
2342 110875149 : class loop *def_loop;
2343 110875149 : basic_block def_bb = gimple_bb (SSA_NAME_DEF_STMT (chrec));
2344 :
2345 : /* A parameter, nothing to do. */
2346 110875149 : if (!def_bb
2347 110875149 : || !dominated_by_p (CDI_DOMINATORS, def_bb, instantiate_below->dest))
2348 47500339 : return chrec;
2349 :
2350 : /* We cache the value of instantiated variable to avoid exponential
2351 : time complexity due to reevaluations. We also store the convenient
2352 : value in the cache in order to prevent infinite recursion -- we do
2353 : not want to instantiate the SSA_NAME if it is in a mixer
2354 : structure. This is used for avoiding the instantiation of
2355 : recursively defined functions, such as:
2356 :
2357 : | a_2 -> {0, +, 1, +, a_2}_1 */
2358 :
2359 63374810 : unsigned si = get_instantiated_value_entry (*global_cache,
2360 : chrec, instantiate_below);
2361 63374810 : if (global_cache->get (si) != chrec_not_analyzed_yet)
2362 : return global_cache->get (si);
2363 :
2364 : /* On recursion return chrec_dont_know. */
2365 32779702 : global_cache->set (si, chrec_dont_know);
2366 :
2367 32779702 : def_loop = find_common_loop (evolution_loop, def_bb->loop_father);
2368 :
2369 32779702 : if (! dominated_by_p (CDI_DOMINATORS,
2370 32779702 : def_loop->header, instantiate_below->dest))
2371 : {
2372 189594 : gimple *def = SSA_NAME_DEF_STMT (chrec);
2373 189594 : if (gassign *ass = dyn_cast <gassign *> (def))
2374 : {
2375 134996 : switch (gimple_assign_rhs_class (ass))
2376 : {
2377 5575 : case GIMPLE_UNARY_RHS:
2378 5575 : {
2379 5575 : tree op0 = instantiate_scev_r (instantiate_below, evolution_loop,
2380 : inner_loop, gimple_assign_rhs1 (ass),
2381 : fold_conversions, size_expr);
2382 5575 : if (op0 == chrec_dont_know)
2383 : return chrec_dont_know;
2384 1392 : res = fold_build1 (gimple_assign_rhs_code (ass),
2385 : TREE_TYPE (chrec), op0);
2386 1392 : break;
2387 : }
2388 54111 : case GIMPLE_BINARY_RHS:
2389 54111 : {
2390 54111 : tree op0 = instantiate_scev_r (instantiate_below, evolution_loop,
2391 : inner_loop, gimple_assign_rhs1 (ass),
2392 : fold_conversions, size_expr);
2393 54111 : if (op0 == chrec_dont_know)
2394 : return chrec_dont_know;
2395 12136 : tree op1 = instantiate_scev_r (instantiate_below, evolution_loop,
2396 : inner_loop, gimple_assign_rhs2 (ass),
2397 : fold_conversions, size_expr);
2398 6068 : if (op1 == chrec_dont_know)
2399 : return chrec_dont_know;
2400 2315 : res = fold_build2 (gimple_assign_rhs_code (ass),
2401 : TREE_TYPE (chrec), op0, op1);
2402 2315 : break;
2403 : }
2404 75310 : default:
2405 75310 : res = chrec_dont_know;
2406 : }
2407 : }
2408 : else
2409 54598 : res = chrec_dont_know;
2410 133615 : global_cache->set (si, res);
2411 133615 : return res;
2412 : }
2413 :
2414 : /* If the analysis yields a parametric chrec, instantiate the
2415 : result again. */
2416 32590108 : res = analyze_scalar_evolution (def_loop, chrec);
2417 :
2418 : /* Don't instantiate default definitions. */
2419 32590108 : if (TREE_CODE (res) == SSA_NAME
2420 32590108 : && SSA_NAME_IS_DEFAULT_DEF (res))
2421 : ;
2422 :
2423 : /* Don't instantiate loop-closed-ssa phi nodes. */
2424 32569288 : else if (TREE_CODE (res) == SSA_NAME
2425 95950815 : && loop_depth (loop_containing_stmt (SSA_NAME_DEF_STMT (res)))
2426 31691138 : > loop_depth (def_loop))
2427 : {
2428 1903241 : if (res == chrec)
2429 1880590 : res = loop_closed_phi_def (chrec);
2430 : else
2431 : res = chrec;
2432 :
2433 : /* When there is no loop_closed_phi_def, it means that the
2434 : variable is not used after the loop: try to still compute the
2435 : value of the variable when exiting the loop. */
2436 1903241 : if (res == NULL_TREE)
2437 : {
2438 1618867 : loop_p loop = loop_containing_stmt (SSA_NAME_DEF_STMT (chrec));
2439 1618867 : res = analyze_scalar_evolution (loop, chrec);
2440 1618867 : res = compute_overall_effect_of_inner_loop (loop, res);
2441 1618867 : res = instantiate_scev_r (instantiate_below, evolution_loop,
2442 : inner_loop, res,
2443 : fold_conversions, size_expr);
2444 : }
2445 284374 : else if (dominated_by_p (CDI_DOMINATORS,
2446 284374 : gimple_bb (SSA_NAME_DEF_STMT (res)),
2447 284374 : instantiate_below->dest))
2448 284374 : res = chrec_dont_know;
2449 : }
2450 :
2451 30666047 : else if (res != chrec_dont_know)
2452 : {
2453 30666047 : if (inner_loop
2454 1282387 : && def_bb->loop_father != inner_loop
2455 31282099 : && !flow_loop_nested_p (def_bb->loop_father, inner_loop))
2456 : /* ??? We could try to compute the overall effect of the loop here. */
2457 334 : res = chrec_dont_know;
2458 : else
2459 30665713 : res = instantiate_scev_r (instantiate_below, evolution_loop,
2460 : inner_loop, res,
2461 : fold_conversions, size_expr);
2462 : }
2463 :
2464 : /* Store the correct value to the cache. */
2465 32590108 : global_cache->set (si, res);
2466 32590108 : return res;
2467 : }
2468 :
2469 : /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW
2470 : and EVOLUTION_LOOP, that were left under a symbolic form.
2471 :
2472 : CHREC is a polynomial chain of recurrence to be instantiated.
2473 :
2474 : CACHE is the cache of already instantiated values.
2475 :
2476 : Variable pointed by FOLD_CONVERSIONS is set to TRUE when the
2477 : conversions that may wrap in signed/pointer type are folded, as long
2478 : as the value of the chrec is preserved. If FOLD_CONVERSIONS is NULL
2479 : then we don't do such fold.
2480 :
2481 : SIZE_EXPR is used for computing the size of the expression to be
2482 : instantiated, and to stop if it exceeds some limit. */
2483 :
2484 : static tree
2485 60664715 : instantiate_scev_poly (edge instantiate_below,
2486 : class loop *evolution_loop, class loop *,
2487 : tree chrec, bool *fold_conversions, int size_expr)
2488 : {
2489 60664715 : tree op1;
2490 121329430 : tree op0 = instantiate_scev_r (instantiate_below, evolution_loop,
2491 : get_chrec_loop (chrec),
2492 60664715 : CHREC_LEFT (chrec), fold_conversions,
2493 : size_expr);
2494 60664715 : if (op0 == chrec_dont_know)
2495 : return chrec_dont_know;
2496 :
2497 120894646 : op1 = instantiate_scev_r (instantiate_below, evolution_loop,
2498 : get_chrec_loop (chrec),
2499 60447323 : CHREC_RIGHT (chrec), fold_conversions,
2500 : size_expr);
2501 60447323 : if (op1 == chrec_dont_know)
2502 : return chrec_dont_know;
2503 :
2504 59668719 : if (CHREC_LEFT (chrec) != op0
2505 59668719 : || CHREC_RIGHT (chrec) != op1)
2506 : {
2507 7843831 : op1 = chrec_convert_rhs (chrec_type (op0), op1, NULL);
2508 7843831 : chrec = build_polynomial_chrec (CHREC_VARIABLE (chrec), op0, op1);
2509 : }
2510 :
2511 : return chrec;
2512 : }
2513 :
2514 : /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW
2515 : and EVOLUTION_LOOP, that were left under a symbolic form.
2516 :
2517 : "C0 CODE C1" is a binary expression of type TYPE to be instantiated.
2518 :
2519 : CACHE is the cache of already instantiated values.
2520 :
2521 : Variable pointed by FOLD_CONVERSIONS is set to TRUE when the
2522 : conversions that may wrap in signed/pointer type are folded, as long
2523 : as the value of the chrec is preserved. If FOLD_CONVERSIONS is NULL
2524 : then we don't do such fold.
2525 :
2526 : SIZE_EXPR is used for computing the size of the expression to be
2527 : instantiated, and to stop if it exceeds some limit. */
2528 :
2529 : static tree
2530 24221394 : instantiate_scev_binary (edge instantiate_below,
2531 : class loop *evolution_loop, class loop *inner_loop,
2532 : tree chrec, enum tree_code code,
2533 : tree type, tree c0, tree c1,
2534 : bool *fold_conversions, int size_expr)
2535 : {
2536 24221394 : tree op1;
2537 24221394 : tree op0 = instantiate_scev_r (instantiate_below, evolution_loop, inner_loop,
2538 : c0, fold_conversions, size_expr);
2539 24221394 : if (op0 == chrec_dont_know)
2540 : return chrec_dont_know;
2541 :
2542 : /* While we eventually compute the same op1 if c0 == c1 the process
2543 : of doing this is expensive so the following short-cut prevents
2544 : exponential compile-time behavior. */
2545 23863663 : if (c0 != c1)
2546 : {
2547 23841580 : op1 = instantiate_scev_r (instantiate_below, evolution_loop, inner_loop,
2548 : c1, fold_conversions, size_expr);
2549 23841580 : if (op1 == chrec_dont_know)
2550 : return chrec_dont_know;
2551 : }
2552 : else
2553 : op1 = op0;
2554 :
2555 23793627 : if (c0 != op0
2556 23793627 : || c1 != op1)
2557 : {
2558 13643502 : op0 = chrec_convert (type, op0, NULL);
2559 13643502 : op1 = chrec_convert_rhs (type, op1, NULL);
2560 :
2561 13643502 : switch (code)
2562 : {
2563 7947068 : case POINTER_PLUS_EXPR:
2564 7947068 : case PLUS_EXPR:
2565 7947068 : return chrec_fold_plus (type, op0, op1);
2566 :
2567 874870 : case MINUS_EXPR:
2568 874870 : return chrec_fold_minus (type, op0, op1);
2569 :
2570 4821564 : case MULT_EXPR:
2571 4821564 : return chrec_fold_multiply (type, op0, op1);
2572 :
2573 0 : default:
2574 0 : gcc_unreachable ();
2575 : }
2576 : }
2577 :
2578 10150125 : return chrec ? chrec : fold_build2 (code, type, c0, c1);
2579 : }
2580 :
2581 : /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW
2582 : and EVOLUTION_LOOP, that were left under a symbolic form.
2583 :
2584 : "CHREC" that stands for a convert expression "(TYPE) OP" is to be
2585 : instantiated.
2586 :
2587 : CACHE is the cache of already instantiated values.
2588 :
2589 : Variable pointed by FOLD_CONVERSIONS is set to TRUE when the
2590 : conversions that may wrap in signed/pointer type are folded, as long
2591 : as the value of the chrec is preserved. If FOLD_CONVERSIONS is NULL
2592 : then we don't do such fold.
2593 :
2594 : SIZE_EXPR is used for computing the size of the expression to be
2595 : instantiated, and to stop if it exceeds some limit. */
2596 :
2597 : static tree
2598 24135749 : instantiate_scev_convert (edge instantiate_below,
2599 : class loop *evolution_loop, class loop *inner_loop,
2600 : tree chrec, tree type, tree op,
2601 : bool *fold_conversions, int size_expr)
2602 : {
2603 24135749 : tree op0 = instantiate_scev_r (instantiate_below, evolution_loop,
2604 : inner_loop, op,
2605 : fold_conversions, size_expr);
2606 :
2607 24135749 : if (op0 == chrec_dont_know)
2608 : return chrec_dont_know;
2609 :
2610 19128084 : if (fold_conversions)
2611 : {
2612 7485029 : tree tmp = chrec_convert_aggressive (type, op0, fold_conversions);
2613 7485029 : if (tmp)
2614 : return tmp;
2615 :
2616 : /* If we used chrec_convert_aggressive, we can no longer assume that
2617 : signed chrecs do not overflow, as chrec_convert does, so avoid
2618 : calling it in that case. */
2619 6987946 : if (*fold_conversions)
2620 : {
2621 8243 : if (chrec && op0 == op)
2622 : return chrec;
2623 :
2624 8243 : return fold_convert (type, op0);
2625 : }
2626 : }
2627 :
2628 18622758 : return chrec_convert (type, op0, NULL);
2629 : }
2630 :
2631 : /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW
2632 : and EVOLUTION_LOOP, that were left under a symbolic form.
2633 :
2634 : CHREC is a BIT_NOT_EXPR or a NEGATE_EXPR expression to be instantiated.
2635 : Handle ~X as -1 - X.
2636 : Handle -X as -1 * X.
2637 :
2638 : CACHE is the cache of already instantiated values.
2639 :
2640 : Variable pointed by FOLD_CONVERSIONS is set to TRUE when the
2641 : conversions that may wrap in signed/pointer type are folded, as long
2642 : as the value of the chrec is preserved. If FOLD_CONVERSIONS is NULL
2643 : then we don't do such fold.
2644 :
2645 : SIZE_EXPR is used for computing the size of the expression to be
2646 : instantiated, and to stop if it exceeds some limit. */
2647 :
2648 : static tree
2649 343041 : instantiate_scev_not (edge instantiate_below,
2650 : class loop *evolution_loop, class loop *inner_loop,
2651 : tree chrec,
2652 : enum tree_code code, tree type, tree op,
2653 : bool *fold_conversions, int size_expr)
2654 : {
2655 343041 : tree op0 = instantiate_scev_r (instantiate_below, evolution_loop,
2656 : inner_loop, op,
2657 : fold_conversions, size_expr);
2658 :
2659 343041 : if (op0 == chrec_dont_know)
2660 : return chrec_dont_know;
2661 :
2662 276758 : if (op != op0)
2663 : {
2664 36076 : op0 = chrec_convert (type, op0, NULL);
2665 :
2666 36076 : switch (code)
2667 : {
2668 1733 : case BIT_NOT_EXPR:
2669 1733 : return chrec_fold_minus
2670 1733 : (type, fold_convert (type, integer_minus_one_node), op0);
2671 :
2672 34343 : case NEGATE_EXPR:
2673 34343 : return chrec_fold_multiply
2674 34343 : (type, fold_convert (type, integer_minus_one_node), op0);
2675 :
2676 0 : default:
2677 0 : gcc_unreachable ();
2678 : }
2679 : }
2680 :
2681 240682 : return chrec ? chrec : fold_build1 (code, type, op0);
2682 : }
2683 :
2684 : /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW
2685 : and EVOLUTION_LOOP, that were left under a symbolic form.
2686 :
2687 : CHREC is the scalar evolution to instantiate.
2688 :
2689 : CACHE is the cache of already instantiated values.
2690 :
2691 : Variable pointed by FOLD_CONVERSIONS is set to TRUE when the
2692 : conversions that may wrap in signed/pointer type are folded, as long
2693 : as the value of the chrec is preserved. If FOLD_CONVERSIONS is NULL
2694 : then we don't do such fold.
2695 :
2696 : SIZE_EXPR is used for computing the size of the expression to be
2697 : instantiated, and to stop if it exceeds some limit. */
2698 :
2699 : static tree
2700 363974128 : instantiate_scev_r (edge instantiate_below,
2701 : class loop *evolution_loop, class loop *inner_loop,
2702 : tree chrec,
2703 : bool *fold_conversions, int size_expr)
2704 : {
2705 : /* Give up if the expression is larger than the MAX that we allow. */
2706 363974128 : if (size_expr++ > param_scev_max_expr_size)
2707 11 : return chrec_dont_know;
2708 :
2709 363974117 : if (chrec == NULL_TREE
2710 505008908 : || automatically_generated_chrec_p (chrec)
2711 725955741 : || is_gimple_min_invariant (chrec))
2712 143027284 : return chrec;
2713 :
2714 220946833 : switch (TREE_CODE (chrec))
2715 : {
2716 110875149 : case SSA_NAME:
2717 110875149 : return instantiate_scev_name (instantiate_below, evolution_loop,
2718 : inner_loop, chrec,
2719 110875149 : fold_conversions, size_expr);
2720 :
2721 60664715 : case POLYNOMIAL_CHREC:
2722 60664715 : return instantiate_scev_poly (instantiate_below, evolution_loop,
2723 : inner_loop, chrec,
2724 60664715 : fold_conversions, size_expr);
2725 :
2726 24221394 : case POINTER_PLUS_EXPR:
2727 24221394 : case PLUS_EXPR:
2728 24221394 : case MINUS_EXPR:
2729 24221394 : case MULT_EXPR:
2730 24221394 : return instantiate_scev_binary (instantiate_below, evolution_loop,
2731 : inner_loop, chrec,
2732 : TREE_CODE (chrec), chrec_type (chrec),
2733 24221394 : TREE_OPERAND (chrec, 0),
2734 24221394 : TREE_OPERAND (chrec, 1),
2735 24221394 : fold_conversions, size_expr);
2736 :
2737 24135749 : CASE_CONVERT:
2738 24135749 : return instantiate_scev_convert (instantiate_below, evolution_loop,
2739 : inner_loop, chrec,
2740 24135749 : TREE_TYPE (chrec), TREE_OPERAND (chrec, 0),
2741 24135749 : fold_conversions, size_expr);
2742 :
2743 343041 : case NEGATE_EXPR:
2744 343041 : case BIT_NOT_EXPR:
2745 343041 : return instantiate_scev_not (instantiate_below, evolution_loop,
2746 : inner_loop, chrec,
2747 343041 : TREE_CODE (chrec), TREE_TYPE (chrec),
2748 343041 : TREE_OPERAND (chrec, 0),
2749 343041 : fold_conversions, size_expr);
2750 :
2751 0 : case ADDR_EXPR:
2752 0 : if (is_gimple_min_invariant (chrec))
2753 : return chrec;
2754 : /* Fallthru. */
2755 0 : case SCEV_NOT_KNOWN:
2756 0 : return chrec_dont_know;
2757 :
2758 0 : case SCEV_KNOWN:
2759 0 : return chrec_known;
2760 :
2761 706785 : default:
2762 706785 : if (CONSTANT_CLASS_P (chrec))
2763 : return chrec;
2764 706785 : return chrec_dont_know;
2765 : }
2766 : }
2767 :
2768 : /* Analyze all the parameters of the chrec that were left under a
2769 : symbolic form. INSTANTIATE_BELOW is the basic block that stops the
2770 : recursive instantiation of parameters: a parameter is a variable
2771 : that is defined in a basic block that dominates INSTANTIATE_BELOW or
2772 : a function parameter. */
2773 :
2774 : tree
2775 87372918 : instantiate_scev (edge instantiate_below, class loop *evolution_loop,
2776 : tree chrec)
2777 : {
2778 87372918 : tree res;
2779 :
2780 87372918 : if (dump_file && (dump_flags & TDF_SCEV))
2781 : {
2782 20 : fprintf (dump_file, "(instantiate_scev \n");
2783 20 : fprintf (dump_file, " (instantiate_below = %d -> %d)\n",
2784 20 : instantiate_below->src->index, instantiate_below->dest->index);
2785 20 : if (evolution_loop)
2786 20 : fprintf (dump_file, " (evolution_loop = %d)\n", evolution_loop->num);
2787 20 : fprintf (dump_file, " (chrec = ");
2788 20 : print_generic_expr (dump_file, chrec);
2789 20 : fprintf (dump_file, ")\n");
2790 : }
2791 :
2792 87372918 : bool destr = false;
2793 87372918 : if (!global_cache)
2794 : {
2795 37938201 : global_cache = new instantiate_cache_type;
2796 37938201 : destr = true;
2797 : }
2798 :
2799 87372918 : res = instantiate_scev_r (instantiate_below, evolution_loop,
2800 : NULL, chrec, NULL, 0);
2801 :
2802 87372918 : if (destr)
2803 : {
2804 37938201 : delete global_cache;
2805 37938201 : global_cache = NULL;
2806 : }
2807 :
2808 87372918 : if (dump_file && (dump_flags & TDF_SCEV))
2809 : {
2810 20 : fprintf (dump_file, " (res = ");
2811 20 : print_generic_expr (dump_file, res);
2812 20 : fprintf (dump_file, "))\n");
2813 : }
2814 :
2815 87372918 : return res;
2816 : }
2817 :
2818 : /* Similar to instantiate_parameters, but does not introduce the
2819 : evolutions in outer loops for LOOP invariants in CHREC, and does not
2820 : care about causing overflows, as long as they do not affect value
2821 : of an expression. */
2822 :
2823 : tree
2824 50597074 : resolve_mixers (class loop *loop, tree chrec, bool *folded_casts)
2825 : {
2826 50597074 : bool destr = false;
2827 50597074 : bool fold_conversions = false;
2828 50597074 : if (!global_cache)
2829 : {
2830 49901744 : global_cache = new instantiate_cache_type;
2831 49901744 : destr = true;
2832 : }
2833 :
2834 50597074 : tree ret = instantiate_scev_r (loop_preheader_edge (loop), loop, NULL,
2835 : chrec, &fold_conversions, 0);
2836 :
2837 50597074 : if (folded_casts && !*folded_casts)
2838 50597074 : *folded_casts = fold_conversions;
2839 :
2840 50597074 : if (destr)
2841 : {
2842 49901744 : delete global_cache;
2843 49901744 : global_cache = NULL;
2844 : }
2845 :
2846 50597074 : return ret;
2847 : }
2848 :
2849 : /* Entry point for the analysis of the number of iterations pass.
2850 : This function tries to safely approximate the number of iterations
2851 : the loop will run. When this property is not decidable at compile
2852 : time, the result is chrec_dont_know. Otherwise the result is a
2853 : scalar or a symbolic parameter. When the number of iterations may
2854 : be equal to zero and the property cannot be determined at compile
2855 : time, the result is a COND_EXPR that represents in a symbolic form
2856 : the conditions under which the number of iterations is not zero.
2857 :
2858 : Example of analysis: suppose that the loop has an exit condition:
2859 :
2860 : "if (b > 49) goto end_loop;"
2861 :
2862 : and that in a previous analysis we have determined that the
2863 : variable 'b' has an evolution function:
2864 :
2865 : "EF = {23, +, 5}_2".
2866 :
2867 : When we evaluate the function at the point 5, i.e. the value of the
2868 : variable 'b' after 5 iterations in the loop, we have EF (5) = 48,
2869 : and EF (6) = 53. In this case the value of 'b' on exit is '53' and
2870 : the loop body has been executed 6 times. */
2871 :
2872 : tree
2873 10608129 : number_of_latch_executions (class loop *loop)
2874 : {
2875 10608129 : edge exit;
2876 10608129 : class tree_niter_desc niter_desc;
2877 10608129 : tree may_be_zero;
2878 10608129 : tree res;
2879 :
2880 : /* Determine whether the number of iterations in loop has already
2881 : been computed. */
2882 10608129 : res = loop->nb_iterations;
2883 10608129 : if (res)
2884 : return res;
2885 :
2886 6982231 : may_be_zero = NULL_TREE;
2887 :
2888 6982231 : if (dump_file && (dump_flags & TDF_SCEV))
2889 1 : fprintf (dump_file, "(number_of_iterations_in_loop = \n");
2890 :
2891 6982231 : res = chrec_dont_know;
2892 6982231 : exit = single_exit (loop);
2893 :
2894 6982231 : if (exit && number_of_iterations_exit (loop, exit, &niter_desc, false))
2895 : {
2896 3511762 : may_be_zero = niter_desc.may_be_zero;
2897 3511762 : res = niter_desc.niter;
2898 : }
2899 :
2900 6982231 : if (res == chrec_dont_know
2901 3511762 : || !may_be_zero
2902 10493993 : || integer_zerop (may_be_zero))
2903 : ;
2904 537697 : else if (integer_nonzerop (may_be_zero))
2905 93 : res = build_int_cst (TREE_TYPE (res), 0);
2906 :
2907 537604 : else if (COMPARISON_CLASS_P (may_be_zero))
2908 537604 : res = fold_build3 (COND_EXPR, TREE_TYPE (res), may_be_zero,
2909 : build_int_cst (TREE_TYPE (res), 0), res);
2910 : else
2911 0 : res = chrec_dont_know;
2912 :
2913 6982231 : if (dump_file && (dump_flags & TDF_SCEV))
2914 : {
2915 1 : fprintf (dump_file, " (set_nb_iterations_in_loop = ");
2916 1 : print_generic_expr (dump_file, res);
2917 1 : fprintf (dump_file, "))\n");
2918 : }
2919 :
2920 6982231 : loop->nb_iterations = res;
2921 6982231 : return res;
2922 10608129 : }
2923 :
2924 :
2925 : /* Counters for the stats. */
2926 :
2927 : struct chrec_stats
2928 : {
2929 : unsigned nb_chrecs;
2930 : unsigned nb_affine;
2931 : unsigned nb_affine_multivar;
2932 : unsigned nb_higher_poly;
2933 : unsigned nb_chrec_dont_know;
2934 : unsigned nb_undetermined;
2935 : };
2936 :
2937 : /* Reset the counters. */
2938 :
2939 : static inline void
2940 0 : reset_chrecs_counters (struct chrec_stats *stats)
2941 : {
2942 0 : stats->nb_chrecs = 0;
2943 0 : stats->nb_affine = 0;
2944 0 : stats->nb_affine_multivar = 0;
2945 0 : stats->nb_higher_poly = 0;
2946 0 : stats->nb_chrec_dont_know = 0;
2947 0 : stats->nb_undetermined = 0;
2948 : }
2949 :
2950 : /* Dump the contents of a CHREC_STATS structure. */
2951 :
2952 : static void
2953 0 : dump_chrecs_stats (FILE *file, struct chrec_stats *stats)
2954 : {
2955 0 : fprintf (file, "\n(\n");
2956 0 : fprintf (file, "-----------------------------------------\n");
2957 0 : fprintf (file, "%d\taffine univariate chrecs\n", stats->nb_affine);
2958 0 : fprintf (file, "%d\taffine multivariate chrecs\n", stats->nb_affine_multivar);
2959 0 : fprintf (file, "%d\tdegree greater than 2 polynomials\n",
2960 : stats->nb_higher_poly);
2961 0 : fprintf (file, "%d\tchrec_dont_know chrecs\n", stats->nb_chrec_dont_know);
2962 0 : fprintf (file, "-----------------------------------------\n");
2963 0 : fprintf (file, "%d\ttotal chrecs\n", stats->nb_chrecs);
2964 0 : fprintf (file, "%d\twith undetermined coefficients\n",
2965 : stats->nb_undetermined);
2966 0 : fprintf (file, "-----------------------------------------\n");
2967 0 : fprintf (file, "%d\tchrecs in the scev database\n",
2968 0 : (int) scalar_evolution_info->elements ());
2969 0 : fprintf (file, "%d\tsets in the scev database\n", nb_set_scev);
2970 0 : fprintf (file, "%d\tgets in the scev database\n", nb_get_scev);
2971 0 : fprintf (file, "-----------------------------------------\n");
2972 0 : fprintf (file, ")\n\n");
2973 0 : }
2974 :
2975 : /* Gather statistics about CHREC. */
2976 :
2977 : static void
2978 0 : gather_chrec_stats (tree chrec, struct chrec_stats *stats)
2979 : {
2980 0 : if (dump_file && (dump_flags & TDF_STATS))
2981 : {
2982 0 : fprintf (dump_file, "(classify_chrec ");
2983 0 : print_generic_expr (dump_file, chrec);
2984 0 : fprintf (dump_file, "\n");
2985 : }
2986 :
2987 0 : stats->nb_chrecs++;
2988 :
2989 0 : if (chrec == NULL_TREE)
2990 : {
2991 0 : stats->nb_undetermined++;
2992 0 : return;
2993 : }
2994 :
2995 0 : switch (TREE_CODE (chrec))
2996 : {
2997 0 : case POLYNOMIAL_CHREC:
2998 0 : if (evolution_function_is_affine_p (chrec))
2999 : {
3000 0 : if (dump_file && (dump_flags & TDF_STATS))
3001 0 : fprintf (dump_file, " affine_univariate\n");
3002 0 : stats->nb_affine++;
3003 : }
3004 0 : else if (evolution_function_is_affine_multivariate_p (chrec, 0))
3005 : {
3006 0 : if (dump_file && (dump_flags & TDF_STATS))
3007 0 : fprintf (dump_file, " affine_multivariate\n");
3008 0 : stats->nb_affine_multivar++;
3009 : }
3010 : else
3011 : {
3012 0 : if (dump_file && (dump_flags & TDF_STATS))
3013 0 : fprintf (dump_file, " higher_degree_polynomial\n");
3014 0 : stats->nb_higher_poly++;
3015 : }
3016 :
3017 : break;
3018 :
3019 : default:
3020 : break;
3021 : }
3022 :
3023 0 : if (chrec_contains_undetermined (chrec))
3024 : {
3025 0 : if (dump_file && (dump_flags & TDF_STATS))
3026 0 : fprintf (dump_file, " undetermined\n");
3027 0 : stats->nb_undetermined++;
3028 : }
3029 :
3030 0 : if (dump_file && (dump_flags & TDF_STATS))
3031 0 : fprintf (dump_file, ")\n");
3032 : }
3033 :
3034 : /* Classify the chrecs of the whole database. */
3035 :
3036 : void
3037 0 : gather_stats_on_scev_database (void)
3038 : {
3039 0 : struct chrec_stats stats;
3040 :
3041 0 : if (!dump_file)
3042 0 : return;
3043 :
3044 0 : reset_chrecs_counters (&stats);
3045 :
3046 0 : hash_table<scev_info_hasher>::iterator iter;
3047 0 : scev_info_str *elt;
3048 0 : FOR_EACH_HASH_TABLE_ELEMENT (*scalar_evolution_info, elt, scev_info_str *,
3049 : iter)
3050 0 : gather_chrec_stats (elt->chrec, &stats);
3051 :
3052 0 : dump_chrecs_stats (dump_file, &stats);
3053 : }
3054 :
3055 :
3056 : /* Initialize the analysis of scalar evolutions for LOOPS. */
3057 :
3058 : void
3059 14897418 : scev_initialize (void)
3060 : {
3061 14897418 : gcc_assert (! scev_initialized_p ()
3062 : && loops_state_satisfies_p (cfun, LOOPS_NORMAL));
3063 :
3064 14897418 : scalar_evolution_info = hash_table<scev_info_hasher>::create_ggc (100);
3065 :
3066 53985084 : for (auto loop : loops_list (cfun, 0))
3067 9292830 : loop->nb_iterations = NULL_TREE;
3068 14897418 : }
3069 :
3070 : /* Return true if SCEV is initialized. */
3071 :
3072 : bool
3073 100558694 : scev_initialized_p (void)
3074 : {
3075 100558694 : return scalar_evolution_info != NULL;
3076 : }
3077 :
3078 : /* Cleans up the information cached by the scalar evolutions analysis
3079 : in the hash table. */
3080 :
3081 : void
3082 23644751 : scev_reset_htab (void)
3083 : {
3084 23644751 : if (!scalar_evolution_info)
3085 : return;
3086 :
3087 6114404 : scalar_evolution_info->empty ();
3088 : }
3089 :
3090 : /* Cleans up the information cached by the scalar evolutions analysis
3091 : in the hash table and in the loop->nb_iterations. */
3092 :
3093 : void
3094 12767911 : scev_reset (void)
3095 : {
3096 12767911 : scev_reset_htab ();
3097 :
3098 62951568 : for (auto loop : loops_list (cfun, 0))
3099 24647835 : loop->nb_iterations = NULL_TREE;
3100 12767911 : }
3101 :
3102 : /* Return true if the IV calculation in TYPE can overflow based on the knowledge
3103 : of the upper bound on the number of iterations of LOOP, the BASE and STEP
3104 : of IV.
3105 :
3106 : We do not use information whether TYPE can overflow so it is safe to
3107 : use this test even for derived IVs not computed every iteration or
3108 : hypotetical IVs to be inserted into code. */
3109 :
3110 : bool
3111 15080954 : iv_can_overflow_p (class loop *loop, tree type, tree base, tree step)
3112 : {
3113 15080954 : widest_int nit;
3114 15080954 : wide_int base_min, base_max, step_min, step_max, type_min, type_max;
3115 15080954 : signop sgn = TYPE_SIGN (type);
3116 15080954 : int_range_max r;
3117 :
3118 15080954 : if (integer_zerop (step))
3119 : return false;
3120 :
3121 30161308 : if (!INTEGRAL_TYPE_P (TREE_TYPE (base))
3122 28040542 : || !get_range_query (cfun)->range_of_expr (r, base)
3123 14020271 : || r.varying_p ()
3124 27477643 : || r.undefined_p ())
3125 2686509 : return true;
3126 :
3127 12394438 : base_min = r.lower_bound ();
3128 12394438 : base_max = r.upper_bound ();
3129 :
3130 24788317 : if (!INTEGRAL_TYPE_P (TREE_TYPE (step))
3131 24788876 : || !get_range_query (cfun)->range_of_expr (r, step)
3132 12394438 : || r.varying_p ()
3133 24710885 : || r.undefined_p ())
3134 77991 : return true;
3135 :
3136 12316447 : step_min = r.lower_bound ();
3137 12316447 : step_max = r.upper_bound ();
3138 :
3139 12316447 : if (!get_max_loop_iterations (loop, &nit))
3140 : return true;
3141 :
3142 11647966 : type_min = wi::min_value (type);
3143 11647966 : type_max = wi::max_value (type);
3144 :
3145 : /* Just sanity check that we don't see values out of the range of the type.
3146 : In this case the arithmetics below would overflow. */
3147 11647966 : gcc_checking_assert (wi::ge_p (base_min, type_min, sgn)
3148 : && wi::le_p (base_max, type_max, sgn));
3149 :
3150 : /* Account the possible increment in the last ieration. */
3151 11647966 : wi::overflow_type overflow = wi::OVF_NONE;
3152 11647966 : nit = wi::add (nit, 1, SIGNED, &overflow);
3153 11647966 : if (overflow)
3154 : return true;
3155 :
3156 : /* NIT is typeless and can exceed the precision of the type. In this case
3157 : overflow is always possible, because we know STEP is non-zero. */
3158 11647966 : if (wi::min_precision (nit, UNSIGNED) > TYPE_PRECISION (type))
3159 : return true;
3160 11402987 : wide_int nit2 = wide_int::from (nit, TYPE_PRECISION (type), UNSIGNED);
3161 :
3162 : /* If step can be positive, check that nit*step <= type_max-base.
3163 : This can be done by unsigned arithmetic and we only need to watch overflow
3164 : in the multiplication. The right hand side can always be represented in
3165 : the type. */
3166 11402987 : if (sgn == UNSIGNED || !wi::neg_p (step_max))
3167 : {
3168 11359404 : wi::overflow_type overflow = wi::OVF_NONE;
3169 11359404 : if (wi::gtu_p (wi::mul (step_max, nit2, UNSIGNED, &overflow),
3170 22718808 : type_max - base_max)
3171 22718808 : || overflow)
3172 5736891 : return true;
3173 : }
3174 : /* If step can be negative, check that nit*(-step) <= base_min-type_min. */
3175 5666096 : if (sgn == SIGNED && wi::neg_p (step_min))
3176 : {
3177 43986 : wi::overflow_type overflow, overflow2;
3178 43986 : overflow = overflow2 = wi::OVF_NONE;
3179 87972 : if (wi::gtu_p (wi::mul (wi::neg (step_min, &overflow2),
3180 : nit2, UNSIGNED, &overflow),
3181 87972 : base_min - type_min)
3182 87972 : || overflow || overflow2)
3183 16372 : return true;
3184 : }
3185 :
3186 : return false;
3187 15080954 : }
3188 :
3189 : /* Given EV with form of "(type) {inner_base, inner_step}_loop", this
3190 : function tries to derive condition under which it can be simplified
3191 : into "{(type)inner_base, (type)inner_step}_loop". The condition is
3192 : the maximum number that inner iv can iterate. */
3193 :
3194 : static tree
3195 40875 : derive_simple_iv_with_niters (tree ev, tree *niters)
3196 : {
3197 40875 : if (!CONVERT_EXPR_P (ev))
3198 : return ev;
3199 :
3200 40875 : tree inner_ev = TREE_OPERAND (ev, 0);
3201 40875 : if (TREE_CODE (inner_ev) != POLYNOMIAL_CHREC)
3202 : return ev;
3203 :
3204 40875 : tree init = CHREC_LEFT (inner_ev);
3205 40875 : tree step = CHREC_RIGHT (inner_ev);
3206 40875 : if (TREE_CODE (init) != INTEGER_CST
3207 40875 : || TREE_CODE (step) != INTEGER_CST || integer_zerop (step))
3208 7783 : return ev;
3209 :
3210 33092 : tree type = TREE_TYPE (ev);
3211 33092 : tree inner_type = TREE_TYPE (inner_ev);
3212 33092 : if (TYPE_PRECISION (inner_type) >= TYPE_PRECISION (type))
3213 : return ev;
3214 :
3215 : /* Type conversion in "(type) {inner_base, inner_step}_loop" can be
3216 : folded only if inner iv won't overflow. We compute the maximum
3217 : number the inner iv can iterate before overflowing and return the
3218 : simplified affine iv. */
3219 33092 : tree delta;
3220 33092 : init = fold_convert (type, init);
3221 33092 : step = fold_convert (type, step);
3222 33092 : ev = build_polynomial_chrec (CHREC_VARIABLE (inner_ev), init, step);
3223 33092 : if (tree_int_cst_sign_bit (step))
3224 : {
3225 0 : tree bound = lower_bound_in_type (inner_type, inner_type);
3226 0 : delta = fold_build2 (MINUS_EXPR, type, init, fold_convert (type, bound));
3227 0 : step = fold_build1 (NEGATE_EXPR, type, step);
3228 : }
3229 : else
3230 : {
3231 33092 : tree bound = upper_bound_in_type (inner_type, inner_type);
3232 33092 : delta = fold_build2 (MINUS_EXPR, type, fold_convert (type, bound), init);
3233 : }
3234 33092 : *niters = fold_build2 (FLOOR_DIV_EXPR, type, delta, step);
3235 33092 : return ev;
3236 : }
3237 :
3238 : /* Checks whether use of OP in USE_LOOP behaves as a simple affine iv with
3239 : respect to WRTO_LOOP and returns its base and step in IV if possible
3240 : (see analyze_scalar_evolution_in_loop for more details on USE_LOOP
3241 : and WRTO_LOOP). If ALLOW_NONCONSTANT_STEP is true, we want step to be
3242 : invariant in LOOP. Otherwise we require it to be an integer constant.
3243 :
3244 : IV->no_overflow is set to true if we are sure the iv cannot overflow (e.g.
3245 : because it is computed in signed arithmetics). Consequently, adding an
3246 : induction variable
3247 :
3248 : for (i = IV->base; ; i += IV->step)
3249 :
3250 : is only safe if IV->no_overflow is false, or TYPE_OVERFLOW_UNDEFINED is
3251 : false for the type of the induction variable, or you can prove that i does
3252 : not wrap by some other argument. Otherwise, this might introduce undefined
3253 : behavior, and
3254 :
3255 : i = iv->base;
3256 : for (; ; i = (type) ((unsigned type) i + (unsigned type) iv->step))
3257 :
3258 : must be used instead.
3259 :
3260 : When IV_NITERS is not NULL, this function also checks case in which OP
3261 : is a conversion of an inner simple iv of below form:
3262 :
3263 : (outer_type){inner_base, inner_step}_loop.
3264 :
3265 : If type of inner iv has smaller precision than outer_type, it can't be
3266 : folded into {(outer_type)inner_base, (outer_type)inner_step}_loop because
3267 : the inner iv could overflow/wrap. In this case, we derive a condition
3268 : under which the inner iv won't overflow/wrap and do the simplification.
3269 : The derived condition normally is the maximum number the inner iv can
3270 : iterate, and will be stored in IV_NITERS. This is useful in loop niter
3271 : analysis, to derive break conditions when a loop must terminate, when is
3272 : infinite. */
3273 :
3274 : bool
3275 51406149 : simple_iv_with_niters (class loop *wrto_loop, class loop *use_loop,
3276 : tree op, affine_iv *iv, tree *iv_niters,
3277 : bool allow_nonconstant_step)
3278 : {
3279 51406149 : enum tree_code code;
3280 51406149 : tree type, ev, base, e;
3281 51406149 : wide_int extreme;
3282 51406149 : bool folded_casts;
3283 :
3284 51406149 : iv->base = NULL_TREE;
3285 51406149 : iv->step = NULL_TREE;
3286 51406149 : iv->no_overflow = false;
3287 :
3288 51406149 : type = TREE_TYPE (op);
3289 51406149 : if (!POINTER_TYPE_P (type)
3290 42239105 : && !INTEGRAL_TYPE_P (type))
3291 : return false;
3292 :
3293 49335508 : ev = analyze_scalar_evolution_in_loop (wrto_loop, use_loop, op,
3294 : &folded_casts);
3295 49335508 : if (chrec_contains_undetermined (ev)
3296 49335508 : || chrec_contains_symbols_defined_in_loop (ev, wrto_loop->num))
3297 12853132 : return false;
3298 :
3299 36482376 : if (tree_does_not_contain_chrecs (ev))
3300 : {
3301 16112720 : iv->base = ev;
3302 16112720 : tree ev_type = TREE_TYPE (ev);
3303 16112720 : if (POINTER_TYPE_P (ev_type))
3304 2678997 : ev_type = sizetype;
3305 :
3306 16112720 : iv->step = build_int_cst (ev_type, 0);
3307 16112720 : iv->no_overflow = true;
3308 16112720 : return true;
3309 : }
3310 :
3311 : /* If we can derive valid scalar evolution with assumptions. */
3312 20369656 : if (iv_niters && TREE_CODE (ev) != POLYNOMIAL_CHREC)
3313 40875 : ev = derive_simple_iv_with_niters (ev, iv_niters);
3314 :
3315 20369656 : if (TREE_CODE (ev) != POLYNOMIAL_CHREC)
3316 : return false;
3317 :
3318 20322498 : if (CHREC_VARIABLE (ev) != (unsigned) wrto_loop->num)
3319 : return false;
3320 :
3321 20322484 : iv->step = CHREC_RIGHT (ev);
3322 12964677 : if ((!allow_nonconstant_step && TREE_CODE (iv->step) != INTEGER_CST)
3323 33030751 : || tree_contains_chrecs (iv->step, NULL))
3324 267781 : return false;
3325 :
3326 20054703 : iv->base = CHREC_LEFT (ev);
3327 20054703 : if (tree_contains_chrecs (iv->base, NULL))
3328 : return false;
3329 :
3330 20054703 : iv->no_overflow = !folded_casts && nowrap_type_p (type);
3331 :
3332 20054703 : if (!iv->no_overflow
3333 20054703 : && !iv_can_overflow_p (wrto_loop, type, iv->base, iv->step))
3334 3790641 : iv->no_overflow = true;
3335 :
3336 : /* Try to simplify iv base:
3337 :
3338 : (signed T) ((unsigned T)base + step) ;; TREE_TYPE (base) == signed T
3339 : == (signed T)(unsigned T)base + step
3340 : == base + step
3341 :
3342 : If we can prove operation (base + step) doesn't overflow or underflow.
3343 : Specifically, we try to prove below conditions are satisfied:
3344 :
3345 : base <= UPPER_BOUND (type) - step ;;step > 0
3346 : base >= LOWER_BOUND (type) - step ;;step < 0
3347 :
3348 : This is done by proving the reverse conditions are false using loop's
3349 : initial conditions.
3350 :
3351 : The is necessary to make loop niter, or iv overflow analysis easier
3352 : for below example:
3353 :
3354 : int foo (int *a, signed char s, signed char l)
3355 : {
3356 : signed char i;
3357 : for (i = s; i < l; i++)
3358 : a[i] = 0;
3359 : return 0;
3360 : }
3361 :
3362 : Note variable I is firstly converted to type unsigned char, incremented,
3363 : then converted back to type signed char. */
3364 :
3365 20054703 : if (wrto_loop->num != use_loop->num)
3366 : return true;
3367 :
3368 19883619 : if (!CONVERT_EXPR_P (iv->base) || TREE_CODE (iv->step) != INTEGER_CST)
3369 : return true;
3370 :
3371 228647 : type = TREE_TYPE (iv->base);
3372 228647 : e = TREE_OPERAND (iv->base, 0);
3373 228647 : if (!tree_nop_conversion_p (type, TREE_TYPE (e))
3374 197109 : || TREE_CODE (e) != PLUS_EXPR
3375 108594 : || TREE_CODE (TREE_OPERAND (e, 1)) != INTEGER_CST
3376 310311 : || !tree_int_cst_equal (iv->step,
3377 81664 : fold_convert (type, TREE_OPERAND (e, 1))))
3378 166001 : return true;
3379 62646 : e = TREE_OPERAND (e, 0);
3380 62646 : if (!CONVERT_EXPR_P (e))
3381 : return true;
3382 34629 : base = TREE_OPERAND (e, 0);
3383 34629 : if (!useless_type_conversion_p (type, TREE_TYPE (base)))
3384 : return true;
3385 :
3386 26831 : if (tree_int_cst_sign_bit (iv->step))
3387 : {
3388 9101 : code = LT_EXPR;
3389 9101 : extreme = wi::min_value (type);
3390 : }
3391 : else
3392 : {
3393 17730 : code = GT_EXPR;
3394 17730 : extreme = wi::max_value (type);
3395 : }
3396 26831 : wi::overflow_type overflow = wi::OVF_NONE;
3397 26831 : extreme = wi::sub (extreme, wi::to_wide (iv->step),
3398 53662 : TYPE_SIGN (type), &overflow);
3399 26831 : if (overflow)
3400 : return true;
3401 26807 : e = fold_build2 (code, boolean_type_node, base,
3402 : wide_int_to_tree (type, extreme));
3403 26807 : e = simplify_using_initial_conditions (use_loop, e);
3404 26807 : if (!integer_zerop (e))
3405 : return true;
3406 :
3407 12970 : if (POINTER_TYPE_P (TREE_TYPE (base)))
3408 : code = POINTER_PLUS_EXPR;
3409 : else
3410 : code = PLUS_EXPR;
3411 :
3412 12970 : iv->base = fold_build2 (code, TREE_TYPE (base), base, iv->step);
3413 12970 : return true;
3414 51406149 : }
3415 :
3416 : /* Like simple_iv_with_niters, but return TRUE when OP behaves as a simple
3417 : affine iv unconditionally. */
3418 :
3419 : bool
3420 21104038 : simple_iv (class loop *wrto_loop, class loop *use_loop, tree op,
3421 : affine_iv *iv, bool allow_nonconstant_step)
3422 : {
3423 21104038 : return simple_iv_with_niters (wrto_loop, use_loop, op, iv,
3424 21104038 : NULL, allow_nonconstant_step);
3425 : }
3426 :
3427 : /* Finalize the scalar evolution analysis. */
3428 :
3429 : void
3430 14897419 : scev_finalize (void)
3431 : {
3432 14897419 : if (!scalar_evolution_info)
3433 : return;
3434 14897418 : scalar_evolution_info->empty ();
3435 14897418 : scalar_evolution_info = NULL;
3436 14897418 : free_numbers_of_iterations_estimates (cfun);
3437 : }
3438 :
3439 : /* Returns true if the expression EXPR is considered to be too expensive
3440 : for scev_const_prop. Sets *COND_OVERFLOW_P to true when the
3441 : expression might contain a sub-expression that is subject to undefined
3442 : overflow behavior and conditionally evaluated. */
3443 :
3444 : static bool
3445 10735088 : expression_expensive_p (tree expr, bool *cond_overflow_p,
3446 : hash_map<tree, uint64_t> &cache, uint64_t &cost)
3447 : {
3448 10735088 : enum tree_code code;
3449 :
3450 10735088 : if (is_gimple_val (expr))
3451 : return false;
3452 :
3453 4547283 : code = TREE_CODE (expr);
3454 4547283 : if (code == TRUNC_DIV_EXPR
3455 : || code == CEIL_DIV_EXPR
3456 : || code == FLOOR_DIV_EXPR
3457 : || code == ROUND_DIV_EXPR
3458 : || code == TRUNC_MOD_EXPR
3459 : || code == CEIL_MOD_EXPR
3460 : || code == FLOOR_MOD_EXPR
3461 4547283 : || code == ROUND_MOD_EXPR
3462 4547283 : || code == EXACT_DIV_EXPR)
3463 : {
3464 : /* Division by power of two is usually cheap, so we allow it.
3465 : Forbid anything else. */
3466 65881 : if (!integer_pow2p (TREE_OPERAND (expr, 1)))
3467 : return true;
3468 : }
3469 :
3470 4537557 : bool visited_p;
3471 4537557 : uint64_t &local_cost = cache.get_or_insert (expr, &visited_p);
3472 4537557 : if (visited_p)
3473 : {
3474 341 : uint64_t tem = cost + local_cost;
3475 341 : if (tem < cost)
3476 : return true;
3477 341 : cost = tem;
3478 341 : return false;
3479 : }
3480 4537216 : local_cost = 1;
3481 :
3482 4537216 : uint64_t op_cost = 0;
3483 4537216 : if (code == CALL_EXPR)
3484 : {
3485 140 : tree arg;
3486 140 : call_expr_arg_iterator iter;
3487 : /* Even though is_inexpensive_builtin might say true, we will get a
3488 : library call for popcount when backend does not have an instruction
3489 : to do so. We consider this to be expensive and generate
3490 : __builtin_popcount only when backend defines it. */
3491 140 : optab optab;
3492 140 : combined_fn cfn = get_call_combined_fn (expr);
3493 140 : switch (cfn)
3494 : {
3495 31 : CASE_CFN_POPCOUNT:
3496 31 : optab = popcount_optab;
3497 31 : goto bitcount_call;
3498 85 : CASE_CFN_CLZ:
3499 85 : optab = clz_optab;
3500 85 : goto bitcount_call;
3501 : CASE_CFN_CTZ:
3502 : optab = ctz_optab;
3503 140 : bitcount_call:
3504 : /* Check if opcode for popcount is available in the mode required. */
3505 140 : if (optab_handler (optab,
3506 140 : TYPE_MODE (TREE_TYPE (CALL_EXPR_ARG (expr, 0))))
3507 : == CODE_FOR_nothing)
3508 : {
3509 27 : machine_mode mode;
3510 27 : mode = TYPE_MODE (TREE_TYPE (CALL_EXPR_ARG (expr, 0)));
3511 27 : scalar_int_mode int_mode;
3512 :
3513 : /* If the mode is of 2 * UNITS_PER_WORD size, we can handle
3514 : double-word popcount by emitting two single-word popcount
3515 : instructions. */
3516 27 : if (is_a <scalar_int_mode> (mode, &int_mode)
3517 29 : && GET_MODE_SIZE (int_mode) == 2 * UNITS_PER_WORD
3518 2 : && (optab_handler (optab, word_mode)
3519 : != CODE_FOR_nothing))
3520 : break;
3521 : /* If popcount is available for a wider mode, we emulate the
3522 : operation for a narrow mode by first zero-extending the value
3523 : and then computing popcount in the wider mode. Analogue for
3524 : ctz. For clz we do the same except that we additionally have
3525 : to subtract the difference of the mode precisions from the
3526 : result. */
3527 25 : if (is_a <scalar_int_mode> (mode, &int_mode))
3528 : {
3529 25 : machine_mode wider_mode_iter;
3530 124 : FOR_EACH_WIDER_MODE (wider_mode_iter, mode)
3531 99 : if (optab_handler (optab, wider_mode_iter)
3532 : != CODE_FOR_nothing)
3533 0 : goto check_call_args;
3534 : /* Operation ctz may be emulated via clz in expand_ctz. */
3535 25 : if (optab == ctz_optab)
3536 : {
3537 0 : FOR_EACH_WIDER_MODE_FROM (wider_mode_iter, mode)
3538 0 : if (optab_handler (clz_optab, wider_mode_iter)
3539 : != CODE_FOR_nothing)
3540 0 : goto check_call_args;
3541 : }
3542 : }
3543 25 : return true;
3544 : }
3545 : break;
3546 :
3547 0 : default:
3548 0 : if (cfn == CFN_LAST
3549 0 : || !is_inexpensive_builtin (get_callee_fndecl (expr)))
3550 0 : return true;
3551 : break;
3552 : }
3553 :
3554 115 : check_call_args:
3555 345 : FOR_EACH_CALL_EXPR_ARG (arg, iter, expr)
3556 115 : if (expression_expensive_p (arg, cond_overflow_p, cache, op_cost))
3557 : return true;
3558 115 : *cache.get (expr) += op_cost;
3559 115 : cost += op_cost + 1;
3560 115 : return false;
3561 : }
3562 :
3563 4537076 : if (code == COND_EXPR)
3564 : {
3565 1899 : if (expression_expensive_p (TREE_OPERAND (expr, 0), cond_overflow_p,
3566 : cache, op_cost)
3567 1899 : || (EXPR_P (TREE_OPERAND (expr, 1))
3568 1898 : && EXPR_P (TREE_OPERAND (expr, 2)))
3569 : /* If either branch has side effects or could trap. */
3570 1891 : || TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1))
3571 1891 : || generic_expr_could_trap_p (TREE_OPERAND (expr, 1))
3572 1890 : || TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 0))
3573 1890 : || generic_expr_could_trap_p (TREE_OPERAND (expr, 0))
3574 1890 : || expression_expensive_p (TREE_OPERAND (expr, 1), cond_overflow_p,
3575 : cache, op_cost)
3576 3697 : || expression_expensive_p (TREE_OPERAND (expr, 2), cond_overflow_p,
3577 : cache, op_cost))
3578 101 : return true;
3579 : /* Conservatively assume there's overflow for now. */
3580 1798 : *cond_overflow_p = true;
3581 1798 : *cache.get (expr) += op_cost;
3582 1798 : cost += op_cost + 1;
3583 1798 : return false;
3584 : }
3585 :
3586 4535177 : switch (TREE_CODE_CLASS (code))
3587 : {
3588 2365060 : case tcc_binary:
3589 2365060 : case tcc_comparison:
3590 2365060 : if (expression_expensive_p (TREE_OPERAND (expr, 1), cond_overflow_p,
3591 : cache, op_cost))
3592 : return true;
3593 :
3594 : /* Fallthru. */
3595 4532436 : case tcc_unary:
3596 4532436 : if (expression_expensive_p (TREE_OPERAND (expr, 0), cond_overflow_p,
3597 : cache, op_cost))
3598 : return true;
3599 4508621 : *cache.get (expr) += op_cost;
3600 4508621 : cost += op_cost + 1;
3601 4508621 : return false;
3602 :
3603 : default:
3604 : return true;
3605 : }
3606 : }
3607 :
3608 : bool
3609 3831890 : expression_expensive_p (tree expr, bool *cond_overflow_p)
3610 : {
3611 3831890 : hash_map<tree, uint64_t> cache;
3612 3831890 : uint64_t expanded_size = 0;
3613 3831890 : *cond_overflow_p = false;
3614 3831890 : return (expression_expensive_p (expr, cond_overflow_p, cache, expanded_size)
3615 : /* ??? Both the explicit unsharing and gimplification of expr will
3616 : expand shared trees to multiple copies.
3617 : Guard against exponential growth by counting the visits and
3618 : comparing againt the number of original nodes. Allow a tiny
3619 : bit of duplication to catch some additional optimizations. */
3620 3841786 : || expanded_size > (cache.elements () + 1));
3621 3831890 : }
3622 :
3623 : /* Match.pd function to match bitwise inductive expression.
3624 : .i.e.
3625 : _2 = 1 << _1;
3626 : _3 = ~_2;
3627 : tmp_9 = _3 & tmp_12; */
3628 : extern bool gimple_bitwise_induction_p (tree, tree *, tree (*)(tree));
3629 :
3630 : /* Return the inductive expression of bitwise operation if possible,
3631 : otherwise returns DEF. */
3632 : static tree
3633 20539 : analyze_and_compute_bitwise_induction_effect (class loop* loop,
3634 : tree phidef,
3635 : unsigned HOST_WIDE_INT niter)
3636 : {
3637 20539 : tree match_op[3],inv, bitwise_scev;
3638 20539 : tree type = TREE_TYPE (phidef);
3639 20539 : gphi* header_phi = NULL;
3640 :
3641 : /* Match things like op2(MATCH_OP[2]), op1(MATCH_OP[1]), phidef(PHIDEF)
3642 :
3643 : op2 = PHI <phidef, inv>
3644 : _1 = (int) bit_17;
3645 : _3 = 1 << _1;
3646 : op1 = ~_3;
3647 : phidef = op1 & op2; */
3648 20539 : if (!gimple_bitwise_induction_p (phidef, &match_op[0], NULL)
3649 102 : || TREE_CODE (match_op[2]) != SSA_NAME
3650 20539 : || !(header_phi = dyn_cast <gphi *> (SSA_NAME_DEF_STMT (match_op[2])))
3651 102 : || gimple_bb (header_phi) != loop->header
3652 20639 : || gimple_phi_num_args (header_phi) != 2)
3653 : return NULL_TREE;
3654 :
3655 100 : if (PHI_ARG_DEF_FROM_EDGE (header_phi, loop_latch_edge (loop)) != phidef)
3656 : return NULL_TREE;
3657 :
3658 100 : bitwise_scev = analyze_scalar_evolution (loop, match_op[1]);
3659 100 : bitwise_scev = instantiate_parameters (loop, bitwise_scev);
3660 :
3661 : /* Make sure bits is in range of type precision. */
3662 100 : if (TREE_CODE (bitwise_scev) != POLYNOMIAL_CHREC
3663 100 : || !INTEGRAL_TYPE_P (TREE_TYPE (bitwise_scev))
3664 100 : || !tree_fits_uhwi_p (CHREC_LEFT (bitwise_scev))
3665 100 : || tree_to_uhwi (CHREC_LEFT (bitwise_scev)) >= TYPE_PRECISION (type)
3666 200 : || !tree_fits_shwi_p (CHREC_RIGHT (bitwise_scev)))
3667 : return NULL_TREE;
3668 :
3669 100 : enum bit_op_kind
3670 : {
3671 : INDUCTION_BIT_CLEAR,
3672 : INDUCTION_BIT_IOR,
3673 : INDUCTION_BIT_XOR,
3674 : INDUCTION_BIT_RESET,
3675 : INDUCTION_ZERO,
3676 : INDUCTION_ALL
3677 : };
3678 :
3679 100 : enum bit_op_kind induction_kind;
3680 100 : enum tree_code code1
3681 100 : = gimple_assign_rhs_code (SSA_NAME_DEF_STMT (phidef));
3682 100 : enum tree_code code2
3683 100 : = gimple_assign_rhs_code (SSA_NAME_DEF_STMT (match_op[0]));
3684 :
3685 : /* BIT_CLEAR: A &= ~(1 << bit)
3686 : BIT_RESET: A ^= (1 << bit).
3687 : BIT_IOR: A |= (1 << bit)
3688 : BIT_ZERO: A &= (1 << bit)
3689 : BIT_ALL: A |= ~(1 << bit)
3690 : BIT_XOR: A ^= ~(1 << bit).
3691 : bit is induction variable. */
3692 100 : switch (code1)
3693 : {
3694 27 : case BIT_AND_EXPR:
3695 27 : induction_kind = code2 == BIT_NOT_EXPR
3696 27 : ? INDUCTION_BIT_CLEAR
3697 : : INDUCTION_ZERO;
3698 : break;
3699 49 : case BIT_IOR_EXPR:
3700 49 : induction_kind = code2 == BIT_NOT_EXPR
3701 49 : ? INDUCTION_ALL
3702 : : INDUCTION_BIT_IOR;
3703 : break;
3704 12 : case BIT_XOR_EXPR:
3705 12 : induction_kind = code2 == BIT_NOT_EXPR
3706 12 : ? INDUCTION_BIT_XOR
3707 : : INDUCTION_BIT_RESET;
3708 : break;
3709 : /* A ^ ~(1 << bit) is equal to ~(A ^ (1 << bit)). */
3710 12 : case BIT_NOT_EXPR:
3711 12 : gcc_assert (code2 == BIT_XOR_EXPR);
3712 : induction_kind = INDUCTION_BIT_XOR;
3713 : break;
3714 0 : default:
3715 0 : gcc_unreachable ();
3716 : }
3717 :
3718 37 : if (induction_kind == INDUCTION_ZERO)
3719 12 : return build_zero_cst (type);
3720 88 : if (induction_kind == INDUCTION_ALL)
3721 12 : return build_all_ones_cst (type);
3722 :
3723 152 : wide_int bits = wi::zero (TYPE_PRECISION (type));
3724 76 : HOST_WIDE_INT bit_start = tree_to_shwi (CHREC_LEFT (bitwise_scev));
3725 76 : HOST_WIDE_INT step = tree_to_shwi (CHREC_RIGHT (bitwise_scev));
3726 76 : HOST_WIDE_INT bit_final = bit_start + step * niter;
3727 :
3728 : /* bit_start, bit_final in range of [0,TYPE_PRECISION)
3729 : implies all bits are set in range. */
3730 76 : if (bit_final >= TYPE_PRECISION (type)
3731 76 : || bit_final < 0)
3732 : return NULL_TREE;
3733 :
3734 : /* Loop tripcount should be niter + 1. */
3735 1296 : for (unsigned i = 0; i != niter + 1; i++)
3736 : {
3737 1220 : bits = wi::set_bit (bits, bit_start);
3738 1220 : bit_start += step;
3739 : }
3740 :
3741 76 : bool inverted = false;
3742 76 : switch (induction_kind)
3743 : {
3744 : case INDUCTION_BIT_CLEAR:
3745 : code1 = BIT_AND_EXPR;
3746 : inverted = true;
3747 : break;
3748 : case INDUCTION_BIT_IOR:
3749 : code1 = BIT_IOR_EXPR;
3750 : break;
3751 : case INDUCTION_BIT_RESET:
3752 : code1 = BIT_XOR_EXPR;
3753 : break;
3754 : /* A ^= ~(1 << bit) is special, when loop tripcount is even,
3755 : it's equal to A ^= bits, else A ^= ~bits. */
3756 12 : case INDUCTION_BIT_XOR:
3757 12 : code1 = BIT_XOR_EXPR;
3758 12 : if (niter % 2 == 0)
3759 : inverted = true;
3760 : break;
3761 : default:
3762 : gcc_unreachable ();
3763 : }
3764 :
3765 : if (inverted)
3766 19 : bits = wi::bit_not (bits);
3767 :
3768 76 : inv = PHI_ARG_DEF_FROM_EDGE (header_phi, loop_preheader_edge (loop));
3769 76 : return fold_build2 (code1, type, inv, wide_int_to_tree (type, bits));
3770 : }
3771 :
3772 : /* Match.pd function to match bitop with invariant expression
3773 : .i.e.
3774 : tmp_7 = _0 & _1; */
3775 : extern bool gimple_bitop_with_inv_p (tree, tree *, tree (*)(tree));
3776 :
3777 : /* Return the inductive expression of bitop with invariant if possible,
3778 : otherwise returns DEF. */
3779 : static tree
3780 74830 : analyze_and_compute_bitop_with_inv_effect (class loop* loop, tree phidef,
3781 : tree niter)
3782 : {
3783 74830 : tree match_op[2],inv;
3784 74830 : tree type = TREE_TYPE (phidef);
3785 74830 : gphi* header_phi = NULL;
3786 74830 : enum tree_code code;
3787 : /* match thing like op0 (match[0]), op1 (match[1]), phidef (PHIDEF)
3788 :
3789 : op1 = PHI <phidef, inv>
3790 : phidef = op0 & op1
3791 : if op0 is an invariant, it could change to
3792 : phidef = op0 & inv. */
3793 74830 : gimple *def;
3794 74830 : def = SSA_NAME_DEF_STMT (phidef);
3795 74830 : if (!(is_gimple_assign (def)
3796 27606 : && ((code = gimple_assign_rhs_code (def)), true)
3797 27606 : && (code == BIT_AND_EXPR || code == BIT_IOR_EXPR
3798 21913 : || code == BIT_XOR_EXPR)))
3799 : return NULL_TREE;
3800 :
3801 6397 : match_op[0] = gimple_assign_rhs1 (def);
3802 6397 : match_op[1] = gimple_assign_rhs2 (def);
3803 :
3804 6397 : if (expr_invariant_in_loop_p (loop, match_op[1]))
3805 221 : std::swap (match_op[0], match_op[1]);
3806 :
3807 6397 : if (TREE_CODE (match_op[1]) != SSA_NAME
3808 6397 : || !expr_invariant_in_loop_p (loop, match_op[0])
3809 315 : || !(header_phi = dyn_cast <gphi *> (SSA_NAME_DEF_STMT (match_op[1])))
3810 212 : || gimple_bb (header_phi) != loop->header
3811 6599 : || gimple_phi_num_args (header_phi) != 2)
3812 6195 : return NULL_TREE;
3813 :
3814 202 : if (PHI_ARG_DEF_FROM_EDGE (header_phi, loop_latch_edge (loop)) != phidef)
3815 : return NULL_TREE;
3816 :
3817 197 : enum tree_code code1
3818 197 : = gimple_assign_rhs_code (def);
3819 :
3820 197 : if (code1 == BIT_XOR_EXPR)
3821 : {
3822 51 : if (!tree_fits_uhwi_p (niter))
3823 : return NULL_TREE;
3824 19 : unsigned HOST_WIDE_INT niter_num;
3825 19 : niter_num = tree_to_uhwi (niter);
3826 19 : if (niter_num % 2 != 0)
3827 10 : match_op[0] = build_zero_cst (type);
3828 : }
3829 :
3830 165 : inv = PHI_ARG_DEF_FROM_EDGE (header_phi, loop_preheader_edge (loop));
3831 165 : return fold_build2 (code1, type, inv, match_op[0]);
3832 : }
3833 :
3834 : /* Do final value replacement for LOOP, return true if we did anything. */
3835 :
3836 : bool
3837 687656 : final_value_replacement_loop (class loop *loop)
3838 : {
3839 : /* If we do not know exact number of iterations of the loop, we cannot
3840 : replace the final value. */
3841 687656 : edge exit = single_exit (loop);
3842 687656 : if (!exit)
3843 : return false;
3844 :
3845 459051 : tree niter = number_of_latch_executions (loop);
3846 459051 : if (niter == chrec_dont_know)
3847 : return false;
3848 :
3849 : /* Ensure that it is possible to insert new statements somewhere. */
3850 343685 : if (!single_pred_p (exit->dest))
3851 39097 : split_loop_exit_edge (exit);
3852 :
3853 : /* Set stmt insertion pointer. All stmts are inserted before this point. */
3854 :
3855 343685 : class loop *ex_loop
3856 687370 : = superloop_at_depth (loop,
3857 420758 : loop_depth (exit->dest->loop_father) + 1);
3858 :
3859 343685 : bool any = false;
3860 343685 : gphi_iterator psi;
3861 769228 : for (psi = gsi_start_phis (exit->dest); !gsi_end_p (psi); )
3862 : {
3863 425543 : gphi *phi = psi.phi ();
3864 425543 : tree rslt = PHI_RESULT (phi);
3865 425543 : tree phidef = PHI_ARG_DEF_FROM_EDGE (phi, exit);
3866 425543 : tree def = phidef;
3867 850411 : if (virtual_operand_p (def))
3868 : {
3869 241383 : gsi_next (&psi);
3870 632672 : continue;
3871 : }
3872 :
3873 347859 : if (!POINTER_TYPE_P (TREE_TYPE (def))
3874 347736 : && !INTEGRAL_TYPE_P (TREE_TYPE (def)))
3875 : {
3876 73738 : gsi_next (&psi);
3877 73738 : continue;
3878 : }
3879 :
3880 110422 : bool folded_casts;
3881 110422 : def = analyze_scalar_evolution_in_loop (ex_loop, loop, def,
3882 : &folded_casts);
3883 :
3884 110422 : tree bitinv_def, bit_def;
3885 110422 : unsigned HOST_WIDE_INT niter_num;
3886 :
3887 110422 : if (def != chrec_dont_know)
3888 35592 : def = compute_overall_effect_of_inner_loop (ex_loop, def);
3889 :
3890 : /* Handle bitop with invariant induction expression.
3891 :
3892 : .i.e
3893 : for (int i =0 ;i < 32; i++)
3894 : tmp &= bit2;
3895 : if bit2 is an invariant in loop which could simple to
3896 : tmp &= bit2. */
3897 149660 : else if ((bitinv_def
3898 74830 : = analyze_and_compute_bitop_with_inv_effect (loop,
3899 : phidef, niter)))
3900 : def = bitinv_def;
3901 :
3902 : /* Handle bitwise induction expression.
3903 :
3904 : .i.e.
3905 : for (int i = 0; i != 64; i+=3)
3906 : res &= ~(1UL << i);
3907 :
3908 : RES can't be analyzed out by SCEV because it is not polynomially
3909 : expressible, but in fact final value of RES can be replaced by
3910 : RES & CONSTANT where CONSTANT all ones with bit {0,3,6,9,... ,63}
3911 : being cleared, similar for BIT_IOR_EXPR/BIT_XOR_EXPR. */
3912 74665 : else if (tree_fits_uhwi_p (niter)
3913 31068 : && (niter_num = tree_to_uhwi (niter)) != 0
3914 31049 : && niter_num < TYPE_PRECISION (TREE_TYPE (phidef))
3915 74665 : && (bit_def
3916 20539 : = analyze_and_compute_bitwise_induction_effect (loop,
3917 : phidef,
3918 : niter_num)))
3919 : def = bit_def;
3920 :
3921 110422 : bool cond_overflow_p;
3922 110422 : if (!tree_does_not_contain_chrecs (def)
3923 35275 : || chrec_contains_symbols_defined_in_loop (def, ex_loop->num)
3924 : /* Moving the computation from the loop may prolong life range
3925 : of some ssa names, which may cause problems if they appear
3926 : on abnormal edges. */
3927 35275 : || contains_abnormal_ssa_name_p (def)
3928 : /* Do not emit expensive expressions. The rationale is that
3929 : when someone writes a code like
3930 :
3931 : while (n > 45) n -= 45;
3932 :
3933 : he probably knows that n is not large, and does not want it
3934 : to be turned into n %= 45. */
3935 145697 : || expression_expensive_p (def, &cond_overflow_p))
3936 : {
3937 76168 : if (dump_file && (dump_flags & TDF_DETAILS))
3938 : {
3939 56 : fprintf (dump_file, "not replacing:\n ");
3940 56 : print_gimple_stmt (dump_file, phi, 0);
3941 56 : fprintf (dump_file, "\n");
3942 : }
3943 76168 : gsi_next (&psi);
3944 76168 : continue;
3945 : }
3946 :
3947 : /* Eliminate the PHI node and replace it by a computation outside
3948 : the loop. */
3949 34254 : if (dump_file)
3950 : {
3951 132 : fprintf (dump_file, "\nfinal value replacement:\n ");
3952 132 : print_gimple_stmt (dump_file, phi, 0);
3953 132 : fprintf (dump_file, " with expr: ");
3954 132 : print_generic_expr (dump_file, def);
3955 132 : fprintf (dump_file, "\n");
3956 : }
3957 34254 : any = true;
3958 : /* ??? Here we'd like to have a unshare_expr that would assign
3959 : shared sub-trees to new temporary variables either gimplified
3960 : to a GIMPLE sequence or to a statement list (keeping this a
3961 : GENERIC interface). */
3962 34254 : def = unshare_expr (def);
3963 34254 : auto loc = gimple_phi_arg_location (phi, exit->dest_idx);
3964 :
3965 : /* Create the replacement statements. */
3966 34254 : gimple_seq stmts;
3967 34254 : def = force_gimple_operand (def, &stmts, false, NULL_TREE);
3968 :
3969 : /* Propagate constants immediately, but leave an unused initialization
3970 : around to avoid invalidating the SCEV cache. */
3971 40995 : if (CONSTANT_CLASS_P (def) && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rslt))
3972 6740 : replace_uses_by (rslt, def);
3973 :
3974 : /* Remove the old phi after the gimplification to make sure the
3975 : SSA name is defined by a statement so that fold_stmt during
3976 : the gimplification does not crash. */
3977 34254 : remove_phi_node (&psi, false);
3978 34254 : gassign *ass = gimple_build_assign (rslt, def);
3979 34254 : gimple_set_location (ass, loc);
3980 34254 : gimple_seq_add_stmt (&stmts, ass);
3981 :
3982 : /* If def's type has undefined overflow and there were folded
3983 : casts, rewrite all stmts added for def into arithmetics
3984 : with defined overflow behavior. */
3985 34254 : if ((folded_casts
3986 425 : && ANY_INTEGRAL_TYPE_P (TREE_TYPE (def))
3987 718 : && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (def)))
3988 34679 : || cond_overflow_p)
3989 : {
3990 2058 : gimple_stmt_iterator gsi2;
3991 2058 : gsi2 = gsi_start (stmts);
3992 18804 : while (!gsi_end_p (gsi2))
3993 : {
3994 16746 : if (gimple_needing_rewrite_undefined (gsi_stmt (gsi2)))
3995 404 : rewrite_to_defined_unconditional (&gsi2);
3996 16746 : gsi_next (&gsi2);
3997 : }
3998 : }
3999 34254 : gimple_stmt_iterator gsi = gsi_after_labels (exit->dest);
4000 34254 : gsi_insert_seq_before (&gsi, stmts, GSI_SAME_STMT);
4001 34254 : if (dump_file)
4002 : {
4003 132 : fprintf (dump_file, " final stmt:\n ");
4004 132 : print_gimple_stmt (dump_file, SSA_NAME_DEF_STMT (rslt), 0);
4005 132 : fprintf (dump_file, "\n");
4006 : }
4007 :
4008 : /* Re-fold immediate uses of the replaced def, but avoid
4009 : CFG manipulations from this function. For now only do
4010 : a single-level re-folding, not re-folding uses of
4011 : folded uses. */
4012 34254 : if (! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rslt))
4013 : {
4014 34253 : gimple *use_stmt;
4015 34253 : imm_use_iterator imm_iter;
4016 34253 : auto_vec<gimple *, 4> to_fold;
4017 68522 : FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, rslt)
4018 34269 : if (!stmt_can_throw_internal (cfun, use_stmt))
4019 34267 : to_fold.safe_push (use_stmt);
4020 : /* Delay folding until after the immediate use walk is completed
4021 : as we have an active ranger and that might walk immediate
4022 : uses of rslt again. See PR122502. */
4023 137026 : for (gimple *use_stmt : to_fold)
4024 : {
4025 34267 : gimple_stmt_iterator gsi = gsi_for_stmt (use_stmt);
4026 34267 : if (fold_stmt (&gsi, follow_all_ssa_edges))
4027 1972 : update_stmt (gsi_stmt (gsi));
4028 : }
4029 34253 : }
4030 : }
4031 :
4032 : return any;
4033 : }
4034 :
4035 : #include "gt-tree-scalar-evolution.h"
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